He was 51.
McMahon was with the Rockland County Sheriff's Office and Corrections Division for 29 years, beginning in corrections in1989, and moved to the Patrol Division as an officer in 1996.
He worked for the Rockland County Drug Task Force from 1998 to 1999 before becoming a well-known and respected crime scene detective in 1999 to present.
"His unexpected passing has left us stunned and heartbroken," the department said. "Godspeed Al."
He is survived by his wife Tracy, and sons Ryan, 10, and Al, 14.
A wake for family and friends will be held from 2 p.m. to 4 p.m. and 7 p.m. to 9 p.m. Monday, Sept. 17, at Higgins Funeral Home, 321 S. Main St., New City.
The funeral will take place at 11:30 a.m., Tuesday, Sept. 18 at St. Anthony's Church, 26, W. Nyack Road, Nanuet. Burial will follow at St. Anthony's Cemetery.
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