Police are investigating what they describe as a murder-suicide at an apartment on the third floor of a complex in northwest Houston on Halloween night. Police said the grandmother was killed, the 8-month-old boy was critically wounded and the boy's father died.

Police said the man, 52-year-old Rodney Bob, arrived at the apartment to deliver diapers for his son. The Harris County Medical Examiner's Office identified the man. Investigators said Bob opened fire and then turned the gun on himself. Police said the baby's 19-year-old mother was not injured.

A neighbor who lives two floors below, Prudence Holt, said violent incidents are rare at the complex. She said members of her family heard three gunshots and children screaming. The infant remained in critical condition as of Monday.

Police said they consider the case a murder-suicide. As of Monday, a motive had not been determined, and the investigation is ongoing.