Police announced the arrests of four people Monday night in connection with the the Sunday kidnapping of two 14-day-old babies that triggered an Amber alert. While the babies–Montana and Matthew Bridges–turned up in Detroit uninjured on Monday, police revealed more details Tuesday about the circumstances surround the kidnapping. Livonia police Capt. Gregory Yon said in a press conference that the babies were recovered in Detroit after being removed from a motel where the mother was staying. However the mother claimed the kidnappers were “acquaintances” that she had left the babies with while she went out for a period of time. When she returned, the babies were gone and she phoned police, according to The Detroit News. An Amber Alert was sent early Monday morning and the babies were dropped off soon after. Yon said a motive was yet unclear. On Tuesday night, Livonia police announced the arrests of four people related to the kidnapping. “This case will be submitted to the Wayne County Prosecutor’s Office for review,” a statement said. The identities of those arrested were not released.