Witnesses tell FOX40 Tina Baiz and her two kids were found near a Motel 6 in Linda.
Baiz and her kids were missing since July 4 when she brought her baby Zeke in for an emergency to Rideout Hospital in Marsville.
"We believe Tina may have overheard a conversation outside of the room discussing the positive result the child had for drugs in his system," Yuba City police spokeswoman Shawna Pavey said.
Baiz left, while baby Zeke still had an IV inserted.
Police would not comment on how the kids are doing now, but they say they are questioning Baiz -- who will likely face charges.
"We need to know exactly what has happened with Zeke and Zoe since the time she left Rideout Hospital until we found her this afternoon," Pavey said.
But police say they could not have found Baiz and the kids without the community's help.
"In cases like this, folks that are out in the community, along with the press, are so important in helping us get the information we need in the timelyest manner possible," Pavey told FOX40.
Police would not say what type of drugs baby Zeke tested positive for.