A woman whose son died in police custody on the weekend believes his arrest by Saskatoon police may have been a mistake.

Brandon Travis Daniels, 19, was arrested Friday just after 6:30 p.m. CST, when police responded to a complaint "regarding possible drunkenness," a police spokeswoman said Sunday.

Daniels, of Leask, Sask., was put into the police lockup and was found unresponsive 12 hours later. The coroner's office pronounced him dead at the scene.

The Saskatoon police department's major crime unit has been called in to investigate the circumstances of Daniels' death, under the oversight of the RCMP. Daniels' mother, Sherry Bird of the Mistawasis First Nation, says investigators should be probing whether police confused her son's medical condition with public intoxication.

Bird said her son suffered from an undiagnosed illness that sometimes left him glassy-eyed and confused. She said a family member notified police about his condition.  

"Like why just assume he was drunk?" she asked. "Why not find out if that's what it was, 'cause they were told — they were told at 1:30 [a.m.] or 2 [a.m.] or whenever. They talked to my nephew [who told them that Brandon] was supposed to be on medication. They could have done something then."

Bird said she doesn't know whether her son's illness could have contributed to his death.

An autopsy, which includes toxicology tests, is being conducted but the results won't be available immediately.

Saskatoon police say it is too early in the investigation to draw any conclusions.