Garden Grove, Calif. ? A man wanted in the stabbing deaths of a couple and a 6-year-old boy who were found in their home with a starving 1-year-old girl has been arrested, police said Friday.

Quang Van Quan, 35, was arrested Wednesday in Houston, police Lt. Mike Handfield said. Quan is considered a primary suspect in the slayings, Handfield said, although investigators were searching for at least one other person. He was booked for investigation of murder.

“The motive was robbery,” Handfield said. He declined to elaborate.

Police found the bodies of Phuong Hung Le, 30, his wife, Trish Dawn Lam, 25, and Lam’s 6-year-old son, Tommy, when they conducted a welfare check May 29 at the family’s Orange County home about 35 miles southeast of Los Angeles.

The couple’s 1-year-old daughter was beaten, dehydrated and wearing a soiled diaper when she was found in the house.