BOSTON -- The Massachusetts State Police issued an Amber Alert for two children who were reported missing at 2:45 p.m. Monday from a Marlborough, Mass., neighborhood.

NewsCenter 5's Jorge Quiroga reported that the two children were identified as Christian Borey, 3, and Grace Trotta, 5. They were reported missing from the area of 144 Pleasant St. in Marlborough.

Police said Christian Borey was located safe in Malden, Mass., Monday evening, but investigators were still searching for Grace Trotta and the couple who allegedly took her from her Marlborough foster home.

Grace was described as a white female, about 3 feet 11 inches, 50 pounds, also with brown hair and brown eyes. Grace was wearing a peach-colored, striped shirt and blue jeans that went to her knees.

Borey was described as a white male, 3 feet 6 inches tall, about 40 pounds, with brown hair and brown eyes.

Police alleged that the children were taken by force by a woman identified as Cathy Trotta, 37, and a male companion, identified as Dennis J. Piper, 43. Cathy Trotta, the mother of Grace, is described as 5 feet 9 inches, about 120 pounds, with blond or orange hair. Piper is described as being 155 pounds, with long brown hair.

"At this point I would assume [the children] are in danger," Marlborough Police Chief Mark Leonard said during a police news conference Monday evening.

Police said the couple went to a Marlborough foster home and, at knifepoint, abucted the two children. Leonard said the couple assaulted the foster mother who lived there, possibly with a billy club and a knife, around the head and back. The foster mother was then tied up and left at the house. One of Trotta's other children remained in the house and is safe. A third child of Trotta's was in another town and is also safe, according to police. Christian Borey is the son of the foster mother living at the home.

The couple allegedly took the foster mother's blue Chevrolet Suburban and later abandoned it at a Dunkin' Donuts.

At one point the couple was believed to be in a white 1989 Oldsmobile Cutlass, but authorities said shortly before 5 p.m. that particular car had been located. The missing children, however, were not found. Authorities said the group was then believed to be in a 1992 white Cadillac DeVille with Massachusetts license plates 81VN32.

The group may have been headed toward Lynn, Mass., authorities said. Police searched an apartment in Lynn for the couple, but turned up nothing.

State police are asking that anyone who may see the children contact the Marlborough police immediately at (508) 485-1212 or 911.

The Massachusetts Amber Alert is an emergency alert system that helps recover abducted children. The plan utilizes an Emergency Alert System to interrupt regular broadcast program and broadcast information that could help recover a child or children. Since adoption of the Amber system in 2002, there have been five successful alert notifications leading to the safe recovery of eight children, according to state police.