Monaghan, Daniel John, passed on Friday, February 12, 2021 at the age of 71, son of the late Richard and Mary (Connolly) Monaghan. Loving husband of Cookie (Vargo) Monaghan. Father of Shawn (Crystal) Monaghan. Brother of Sheila (Gary) Mackey and Joseph (Donna) Monaghan. Dan was a United States Marine Corps Veteran serving during the Vietnam War. He was a member of the Allegheny County Police Department for twenty-eight years, retiring at the rank of Sergeant. Dan continued to work in Law Enforcement serving briefly with the Federal Reserve Bank as a Federal Police Officer before being hired by the Commonwealth of Pennsylvania, Bureau of Enforcement and Investigation. Dan served there thirteen years, retiring as an Investigator Supervisor. His combined service in both Criminal and Administrative Law Enforcement totaled forty-two years. Friends and Family will be received at Copeland's Coraopolis, 867 Fifth Ave. on Thursday from 2-4 & 6-8 PM, where a Funeral Service will be held on Friday at 10 am. Interment will be at Resurrection Cemetery, Moon Township, PA. In lieu of flowers, contributions may be made to St. Jude Children’s Hospital, 501 St. Jude Place, Memphis, TN 38105.