The families of two slain New York City police officers threw out the ceremonial first pitch at the Mets’ home opener at Citi Field on Monday and were joined by Mayor Bill de Blasio at a time when his relationship with the police department is again coming under scrutiny.

De Blasio’s relations with the police unions and some rank-and-file officers were fractured in the aftermath of the December shooting that claimed the lives of Officers Rafael Ramos and Wenjian Liu. Since that crisis, which threatened to overwhelm the mayor’s agenda, de Blasio has taken pains to repair relations with the nation’s largest police force, brokering a new union contract, investing in new technology and training, and doubling down on his public praise of the department.

On Monday, he joined the tens of thousands of fans in cheering as the officers’ images were displayed on the park’s giant video screens and again when Ramos’ two sons and Liu’s widow threw out the pitches to Mets players David Wright, Matt Harvey and Curtis Granderson.

De Blasio, however, was largely booed when he was introduced to the crowd.

A year ago, de Blasio was also booed as he threw out the first pitch (a strike). Both years, he sported a Mets cap and jersey, which was emblazoned with his last name and the number 6, a tribute to Rico Petrocelli, a longtime shortstop on de Blasio’s favorite team, the Boston Red Sox. Petrocelli, like de Blasio, was also of Italian descent and lived in Brooklyn.

The tribute to the NYPD comes as de Blasio is weighing a City Council proposal to hire 1,000 more police officers. The idea has been endorsed by union leaders who said it would reduce pressure on existing officers to keep crime low.

But de Blasio rejected an identical council proposal a year ago, pointing to the city’s record low crime and suggesting that the money would be better spent elsewhere.

Police Commissioner William Bratton has, at times, signaled support for the effort to hire more officers for the department, which now has a headcount of about 34,500, about 6,000 fewer than at its peak in 2001. De Blasio has not committed to hiring more officers but has been more receptive to the proposal in his public remarks than he was a year ago.

The council’s budget office projected that hiring two new classes of officers, to total 1,000, would cost nearly $69 million in the upcoming fiscal year. But the council believes that the cost will be offset by the corresponding reduction in overtime.

Though the city’s overall crime rate has fallen again, murders are up nearly 12 percent from this time a year ago, and shootings have also increased, according to NYPD crime statistics. The mayor is expected to offer a counter-proposal next month and a budget deal must be completed by the end of June.

(AP)