BRAINTREE — A large American flag fluttered gently in the cold breeze and the sound of bagpipes filled the air late Sunday afternoon as hundreds of police officers from Boston and surrounding communities marched to a church in Braintree to pay their respects to Officer John O’Keefe, who died late last month.

O’Keefe, 46, a 16-year veteran of the Boston Police Department, was described by friends and colleagues as a family man.

Hundreds lined outside the Church of St. Francis of Assisi, where a wake was held for O’Keefe, who died on January 29. A funeral mass is scheduled for Monday at 11:30 a.m. at the church, according to an obituary. , and the officer will be buried in Blue Hill Cemetery in Braintree.

A dozen Boston police cruisers were parked nearby Sunday on Washington Street, many with their flashing blue and white lights.

Hundreds of Boston police officers line up to attend Boston Police Officer John O’Keefe, III’s funeral wake at St. Francis of Assisi Church on Sunday.Matthew J Lee/Globe Staff

As the sun went down, their lights pierced the dusk against flashing red lights from a pair of Braintree Fire Department ladder trucks parked outside the church. The ladders stretched into the sky and held up an American flag which the officers passed under as they lined up in two columns and marched into the church.

Boston Mayor Michelle Wu stood next to Boston Police Chief Superintendent Gregory Long and they both led the officers into the church. Wu and Long remained inside as officers, including some from departments outside of Boston, entered and walked past O’Keefe’s casket.

More than 300 people lined up to witness the wake of Boston Police Officer John O’Keefe, III at St. Francis of Assisi Church on Sunday.Matthew J Lee/Globe Staff

A friend last week described O’Keefe as a “hero” who adopted his niece and nephew following the death of his sister and brother-in-law within months of separate medical conditions. An online fundraiser set up to support O’Keefe’s niece and nephew had raised more than $247,000 by Sunday night.

O’Keefe’s girlfriend, Karen A. Read, 41, is believed to have played a role in his death and is facing charges. Officials say Read hit him with a car around midnight and left him outside a house in Canton during a powerful snowstorm.

She was arraigned in Stoughton District Court on Wednesday for manslaughter, leaving the scene after causing bodily injury or death, and misdemeanor, motor vehicle homicide. Read, an assistant professor of finance at Bentley University in Waltham and an equity analyst at a financial firm, pleaded not guilty and was released on $50,000 bond.

Prosecutors said Read returned to where she left him hours later and found the officer unconscious in the snow early in the morning of January 29. After her arraignment, Read’s attorney said she had “no criminal intent” and was innocent of the charges.

A police affidavit describes a night of bar-hopping on Friday that ended when Read dropped O’Keefe off at an after-party at a Canton home at 34 Fairview Road.

According to the affidavit, Read told a girlfriend that she had little recollection the next morning of the alcohol-fueled events of the previous night when she frantically began texting and calling O’Keefe to find out. why he had not returned to his home in Canton.

When Read and two girlfriends found O’Keefe, he was face up and unconscious, according to the affidavit. Read said she lay on top of him in an attempt to warm his body and gave him CPR, according to the affidavit.

O’Keefe was later pronounced dead at Good Samaritan Hospital. The cause of death, according to prosecutors, was skull fractures, with hypothermia being a contributing factor.

Material from previous Globe stories has been used in this report.

Nick Stoico can be contacted at [email protected] Follow him on Twitter @NickStoico.