Thousands of police officers waited in the rain to pay their respects at Wednesday's funeral for slain New York City Police Officer Randolph Holder, who was shot and killed while on patrol a week ago.

The service for 33-year-old Holder, who was killed in the city's East Harlem neighborhood, began Wednesday afternoon at the Greater Allen A.M.E. Cathedral of New York. Holder is the fourth New York City officer to be killed on duty in the last 12 months.

Mayor Bill de Blasio and police Commissioner William Bratton stood in silence alongside thousands of officers from multiple police forces who lined the streets outside of the church while awaiting the arrival of Holder's body.

Bagpipes played and a sea of blue-capped officers saluted as Holder's body was carried into the church in a coffin draped in a U.S. flag and flag from his native Guyana.

NYPD officers gave each other long hugs and clapped each other's backs as they entered the church.

"It's an honor just to be invited, just to come down and share the moment with my colleagues," said Sergeant Paul Jennings, 42.

Holder's wake on Tuesday in the city's borough of Queens drew hundreds of police officers who waited in a line four blocks long to pay their respects inside the church.

Tyrone Howard, the 30-year-old suspect in the murder, was indicted by a grand jury on Tuesday, according to prosecutors. He is scheduled to be in court on Nov. 24 on charges of murder and robbery.

His defense lawyer said Howard denies the allegations.

The Rev. Al Sharpton, a prominent civil rights leader and critic of police treatment of minorities, on Tuesday canceled plans to be the eulogist at Holder's funeral, saying he was concerned that his presence would be more divisive than unifying.

Holder was a third-generation police officer. His grandfather and father served as officers in Guyana. Holder's body will be flown to Guyana for burial after Wednesday's service.

News that Howard had avoided prison for selling crack cocaine by participating in a drug diversion program drew sharp criticism last week from city officials. De Blasio on Friday proposed changes to state law that he said would ensure dangerous criminals remain behind bars.

Advocates for the diversion program, which offers treatment as an alternative to incarceration for drug addicts, have warned against making major policy changes based on one incident.

(Reporting by Elizabeth Barber; Writing by Laila Kearney; Editing by Toni Reinhold and Eric Beech)