Investigators have obtained a blood sample from Odom, which will be submitted for testing to the Las Vegas Metropolitan Police laboratory.
"At this point, the case is ongoing," Wehrly said.
On a 911 call played at a news conference, a woman says she also saw Odom take 10 herbal supplement tablets over three days.
Odom was found on Tuesday, the fourth day, lying in bed on his side, with a pinkish fluid coming from his mouth and nose, callers told 911 operators.
He was taken to a hospital in Las Vegas, about an hour's drive from Crystal.
Pahrump Valley Fire Rescue Chief Scott Lewis told reporters there were no incidents as Odom was driven from a hospital in Pahrump to Las Vegas.
Reality television star Khloe Kardashian will make medical decisions for the former NBA star, a source close to Kardashian said Wednesday.
The couple's divorce has not been finalized, the source told CNN.
Kardashian's mother, Kris Jenner, posted a message to Instagram.
"Please pray for Lamar #ourfighter," she wrote.
Odom's father and two children are with him at the hospital, the source said.
Odom, who won two NBA championships and appeared in reality TV shows with Kardashian, was found unresponsive Tuesday afternoon at the Love Ranch in Crystal, authorities said.
"When they took him to the Pahrump hospital, the people there told us, 'He doesn't look good. He doesn't look like he'll make it, and if he does, he won't be the same,' " brothel owner Dennis Hof said.
Officials haven't said what was wrong with Odom, and his condition remains unclear.
The Rev. Jesse Jackson, who visited Odom on Wednesday morning, said the former basketball star was on life support and is not conscious.
Authorities originally planned to fly him to Sunrise Hospital & Medical Center in Las Vegas, but said the 6-foot-10 Odom was too tall to fit in a helicopter.An ambulance then took him to the facility, about 60 miles away from Pahrump.
Odom, 35, won two NBA championships as a forward for the Los Angeles Lakers.
He married the younger sister of Kim Kardashian after a whirlwind romance in 2009. Khloe Kardashian filed for divorce four years later, citing irreconcilable differences. The two reportedly signed divorce papers in July; the source close to Kardashian said the divorce is not final.
Khloe Kardashian has been at the hospital by Odom's side since Tuesday night, according to a source close to the reality star. She asked that people keep him in their thoughts and prayers and respect his privacy, the source said.
Hof said Odom called him Saturday and told him he wanted to visit the brothel for a few days. Hof let him stay at his home, which is attached to the brothel.
"He was having a good time at the ranch and everything was great," Hof said, until Sunday, when Odom seemed "a bit somber" because people were "calling and bothering him."
On Tuesday, about 3:15 p.m., two women went to his room, Hof said.
"Two women at the brothel went to check on Odom and found him unconscious," he said. "They immediately call 911, and dispatch tells the girls to roll him over on his left side and (he) starts to puke. He was totally unconscious. The girls and staff rush him out on the ambulance. The police didn't find any illegal drugs on him."
He added, "To my knowledge, there were no drugs involved. Lamar was eating well and was just healthy."
The site manager of the brothel told CNN that when he arrived in the room the former athlete was on his right side and wouldn't wake up when people shook him.
Richard Hunter said Odom was snoring loudly, had his eyes closed and was unresponsive, so he called 911.
Hunter said the two women, who had been with Odom earlier, handed him a bottle of a legal herbal supplement that is sold at the brothel.
Brothels are legal in Nevada in counties with fewer than 700,000 people, according to state law. Hof and the sex workers from another of his brothels, Moonlite Bunny Ranch outside Carson City, have been featured in HBO documentaries, including "Cathouse" and "Cathouse 2: Back in the Saddle," along with an HBO series employing the same name.
In addition to appearing on "Keeping Up With the Kardashians," Odom and Kardashian had their own reality show, "Khloe & Lamar." It lasted for two seasons and 20 episodes.
Despite going separate ways, Kardashian has said she will always love him.
"I will never, ever not love Lamar," she told E!, which airs their reality shows. "I was so obsessed with him in a healthy way. He was my husband, and I still wish he was."
Kardashian has expressed concerns for him, especially after his best friend died this year.
Despite her family's objection, she regularly talked to her ex-husband by phone during episodes of "Keeping Up With the Kardashians" this season.
Odom touted the help of his "very strong wife" in a 2011 Los Angeles Times article about a tragic two days for the hoopster in which he attended his 24-year-old slain cousin's funeral one day and was involved the next in an automobile accident. His SUV had collided with a motorcycle that struck a 15-year-old pedestrian, Awsaf Alvi Islam.
Odom recalled for the newspaper a series of tragedies: his mother dying of colon cancer when he was 12, the grandmother who raised him dying in 2004 and his infant son, Jayden, dying of sudden infant death syndrome two years later. They were in addition to aunts, cousins and friends "taken away from me," he told the paper.
"Death always seems to be around me," Odom said during the interview. "I've been burying people for a long time."
Odom's collegiate basketball career began with controversy. He played for the University of Rhode Island Rams for the 1998-1999 season after sitting out a year following allegations of recruitment violations by the University of Nevada-Las Vegas, according to reports.As a 17-year-old prospect, he also received a 1997 citation for soliciting prostitutes, the Las Vegas Review-Journal reported.
After a season with Rhode Island, he was drafted by the Los Angeles Clippers in 1999, playing for the team for four seasons before signing with the Miami Heat.
Odom played for four teams during his 14 seasons in the NBA and won the Sixth Man of the Year Award during the 2010-11 season.
"Lamar Odom was one of the greatest people I've ever known," New York Knicks coach and former teammate Derek Fisher said. "That's the way I see him. I don't see him through the prism of choices he has made. I view him through the heart and soul of the person he really is."
Fellow NBA player Dwyane Wade said he was up late, worried about his friend and former Miami teammate.
"I can't help but to be up right now ... ," he tweeted early Wednesday. "On my knees praying ... please God let him pull through."
After one season in Miami, Odom was traded to the Lakers and was a key part of their championship teams in 2009 and 2010.
A year later, he played briefly for the Dallas Mavericks before returning to the Clippers for one season. He has not played in the NBA since then, though the New York Knicks signed him to a two-year contract during the 2014 offseason, only to cut him three months later.
Team President Phil Jackson said at the time that it was "necessary to free up the roster spot" after Odom, whom Jackson had coached when he was with the Lakers, "was unable to uphold the standards to return as an NBA player."
Outside of basketball, Odom has continued making headlines, including for a drunken driving charge two years ago. He pleaded no contest and received three years' probation.
CNN's Kyung Lah reporteed from Crystal, Nevada. CNN's Steve Almasy, Eliott C. McLaughlin and Faith Karimi reported and wrote in Atlanta. CNN's Carolyn Sung, Lisa Respers-France, Artemis Moshtaghian, Dave Alsup, Traci Tamura, Styke Dimas and Justin Lear contributed to this report.