(AP) -- The wife and two sons of a policeman gunned down along with his partner in a brazen daylight ambush were joined at his wake Friday by hundreds of uniformed officers, including dozens who saluted as his flag-draped casket was carried into the church.

The daylong tribute to Officer Rafael Ramos occurred at a Queens church where friends and colleagues spoke of him as an embodiment of the selfless, compassionate and heroic nature the New York Police Department wants its finest officers to project.

"He was studying to be a pastor. He had Bible study books in his locker, which is rare for a police officer, but that goes to show you the type of man he was," NYPD Capt. Sergio Centa said before entering Christ Tabernacle Church.

Ramos' funeral is scheduled for Saturday. Vice President Joe Biden is expected to attend, along with Mayor Bill de Blasio.

Police union officials have criticized de Blasio, saying he contributed to a climate of mistrusting police that set the stage for the killings.

But de Blasio has stood solidly behind the department since the Dec. 20 slayings of Ramos and Officer Wenjian Liu as they sat in their patrol car on a Brooklyn street. The shooter, Ismaaiyl Brinsley, later killed himself.

After the killings, de Blasio called for a temporary halt to demonstrations against police after grand juries in Missouri and on Staten Island declined to charge white police officers in the deaths of two black men.

He denounced as "divisive" a demonstration that took place anyway and on Thursday tweeted a thank you to police for arresting a man accused of threatening to kill officers.

Pastor Ralph Castillo said Ramos was a beloved member of the church.

"Whether he was helping a mom with a carriage or bringing someone to their seats, he did it with so much love and so much vigor and so much joy," Castillo said.

In the evening, hundreds of additional mourners were expected to spill into the streets outside the church to hear speakers eulogize Ramos and to watch on giant video screens.

Ramos was a long-standing and deeply committed member of the church, where he served as an usher, family and friends said.

"We feel sorry for the family, and nobody deserves to die like this," said fellow churchgoer Hilda Kiefer as she waited to enter the wake.

His compassion was in contrast to the emotionally disturbed loner who killed the officers.

Investigators say Brinsley started his rampage by shooting and wounding an ex-girlfriend in Baltimore. He also posted online threats to police and made references to high-profile cases of unarmed black men killed by white officers.

The killings ramped up emotions in the already tense national debate over police conduct. Since Ramos and Liu were killed, police in New York say they have arrested seven people accused of threatening officers.

Liu's funeral arrangements have yet to be announced.

Ramos celebrated his 40th birthday this month. He joined the NYPD in 2012 after working as a school security officer.

The lifelong Brooklyn resident was married with two sons: a 13-year-old who is in middle school and one who attends Bowdoin College in Maine.

The Silver Shield Foundation, a charity founded by the late New York Yankees owner George Steinbrenner, has set aside $40,000 for the education of Ramos' sons. Bowdoin College said it will cover Ramos' older son's education costs as long as he remains a student there.

The Stephen Siller Tunnel to Towers Foundation, a charity created after 9/11, says it will pay off the home mortgages of the two slain officers.

Meanwhile, Centa said he's instructed officers at the 84th Precinct where Ramos and Liu worked to be vigilant on patrol.

"Things we took for granted maybe a week or two ago we can't take for granted anymore," Centa said. "You may be in your car and see someone walking up the street toward you. You have to be prepared. You never know. It's a scary time for the police department right now."