(CNN) -- Police have identified those involved in an incident in which the ice bucket challenge trend was used to trick an autistic teenager into being drenched with a bucket of urine, feces and spit.
Authorities are not yet releasing the names, and are not discussing potential charges as the investigation is not yet complete, said Bay Village, Ohio, Police Chief Mark Spaetzel.
"We are conducting a comprehensive investigation," Spaetzel told CNN Tuesday.
Three celebrities have offered a reward to find those responsible.
Jenny McCarthy and Donnie Wahlberg joined Drew Carey on Sunday in offering $10,000 each.
Bay Village is a suburb of Cleveland, Carey's hometown and the city where "The Drew Carey Show" was based.
A video of the prank shows the teen standing outside a garage door in his underwear when someone from the rooftop dumps a bucket of murky brown fluid over his head.
The 15-year-old boy's mother told CNN affiliate WJW-TV in Cleveland that the video was discovered on her son's cell phone.
"He was embarrassed because he did not know what the contents were until afterwards, and then he didn't want anybody to know," the mother told the station. "They used his phone to tape it, and they put it up on Instagram."
The stunt appears to be a spoof of the ALS ice bucket challenge in which participants get a bucket of ice water dumped over their heads. The campaign raises awareness and donations for research on Amyotrophic lateral sclerosis, also known as Lou Gehrig's disease. According to the ALS Association, the Ice Bucket Challenge has raised more than $110 million.
The Bay Village police said it has been interviewing witnesses and trying to identify those involved.
"Preliminary information suggests this occurred prior to the start of the school year at a home in Bay Village," the department said.
"We understand the collective community anger. It is the hope of our community that this anger will be channeled into a positive action and supporting organizations such as Autism Speaks."
The Bay Village Schools superintendent said the school district is "heartsick over the cruel actions taken against one of our students."
"Many of our students and staff members have been participating in fundraising for ALS through the Ice Bucket Challenge," Superintendent Clint Keener wrote. "It hurts us deeply to see such a wonderful effort twisted to deliberately cause someone pain."