Updated

Police in Wyoming say they are investigating a letter written by a 77-year-old man who shot three people at the senior citizen apartment complex where he lived before killing himself.

Cheyenne Police Department spokesman Dan Long did not comment Thursday on what the letter said.

Larry Rosenberg gave the letter to complex resident Mary Eastman before he opened fire.

Eastman says Rosenberg expressed frustration in the letter about poker parties being held in a common area of the complex.

Long says police believe there may have been what he called "longstanding animosity" between Rosenberg and the victims.

A complex employee was killed and two residents were wounded in the shootings Wednesday. They have not been identified.

Police say Rosenberg shot himself with a handgun as they approached him.