The attempted kidnapping happened just before 3 p.m. Saturday when a woman, her fiance and their two small children were in a car backing out of a parking stall in the Costco parking lot in the 1700 block of Hacienda Drive in Vista, according to Sgt. Nanette McMasters of the San Diego County Sheriff's Department.
A man opened the rear door and tried to remove one of the children, McMasters said. The parents exited the vehicle and confronted the man.
"He opened up the back door, reached in and grabbed my kid," said the boy's father, Peter Kopcak.
Kopcak said the man was trying to grab the car seat with the child in it and Kopcak jumped out and stopped him.
The incident drew a crowd during the physical confrontation between the father and the suspect, the sergeant said.
"An off-duty sheriff's employee and other witnesses intervened, separating the two until deputies from the Vista Sheriff's Station arrived on the scene,'' McMasters said.
Adam Glavinic, 37, was arrested on suspicion of attempted kidnapping and being under the influence of a controlled substance, McMasters said.
Glavinic was booked into the Vista Detention Facility. He has been released on $100,000 bail.