A retired U.S. Army officer is suspected of killing his wife in Bel Air and his son — University of Maryland junior Farhad Siddique — in College Park before taking his own life Wednesday, police said.

Police identified Nasir Siddique, 57, as the suspect, calling the case a domestic murder-suicide. Officials found Nasir and Farhad Siddique dead on the scene in a red Jeep parked near the Parkside Apartments near the 8100 block of 48th Avenue, and found Nasir's wife Zarqa Siddique dead in a bathtub in their Bel Air home, with a gunshot wound to the head.

The Prince George's County Police and Harford County Sheriff's Office are currently investigating. Police have yet to release a motive.

"We have no clear determination on what caused Mr. Siddique to commit these atrocities," said Maj. William Davis of the Harford County Sheriff's Office.

Nasir's brother, Aasi Tahir Siddique, told The Baltimore Sun on Thursday that his brother sent him a text message Wednesday morning telling him he was under stress related to his job. Nasir also told his brother that he was depressed due to their mother's death in March .

"This is just unbelievable," Aasi Tahir Siddique told The Baltimore Sun. "I just can't figure this out."

Davis said the police had no knowledge of any previous calls to the house for disturbances. He added that police collected notes from the house as part of the investigation to determine a motive.

Nasir Siddique was serving as a commissioner on the Governor's Commission on Maryland Military Monuments, as well as working in the environmental branch of the public works department at Aberdeen Proving Ground, at the time of his death. After originally being appointed as a commissioner in 2012, he was not scheduled to be reappointed due to poor attendance, officials told The Diamondback.

His 19-year-old son, Farhad, was a junior neurobiology and physiology major at this university, and Zarqa Siddique, 48, worked for the Howard County Public Schools as an inclusion helper who supported students with severe disabilities. Farhad would have turned 20 years old on Thursday.

A spokesman for Gov. Larry Hogan called the incident "an unspeakable tragedy."

Nasir Siddique had a long, successful career in the military, serving in various roles from 1981 until 2010, according to his military service records. He achieved the rank of lieutenant colonel as a preventive medicine officer for the Medical Service Corps.

He was well-decorated as well, winning numerous awards, including the prestigious Legion of Merit award, given for outstanding conduct and performance. It is ranked sixth in order of precedence for U.S. military awards.

Among other awards, he earned four meritorious service medals, two army commendation medals and a global war on terrorism service medal.

After initially joining the Army in 1981, he joined Kansas State University's ROTC program in 1985, according to his records. He proceeded to serve in Army positions around the nation, including at the Aberdeen Proving Ground in Maryland, Fort Sam Houston in San Antonio, Texas, Fort Lee in Virginia and Fort Belvoir in Virginia. He finished his Army service in Washington.