The game came down to a last-second heave by the Dallas Mavericks’ Dirk Nowitzki that caromed high off the rim before falling through for the winning shot.

It was about as bad as things could get for the Knicks, and then their nightmare season somehow got worse.

Across town, the New York City police said, at around the same time that the Knicks were falling further out of playoff contention, the estranged wife of the starting point guard Raymond Felton was meeting with the police at the 20th Precinct station house in Manhattan.

The divorce lawyer for Ariane Raymondo-Felton had already provided the police with an unlicensed gun that Raymondo-Felton said belonged to her husband.

She told them that it was being kept in their apartment. The couple was in the process of divorcing, a law enforcement official said.

The gun, the police said, contained 18 rounds of live ammunition. Raymondo-Felton told the police in her initial statement that Felton had threatened her with it, the official said. It was not immediately clear when or where she said the threats took place.

At 12:50 a.m., Felton turned himself in at the same station house and remained in police custody for the next 18 hours as he awaited arraignment in Manhattan criminal court.

Late Tuesday afternoon, Felton appeared before Judge Diana Boyar to answer charges of one count of criminal possession of a firearm and one count of criminal possession of a weapon in the third degree.

The top charge carries a maximum penalty of seven years in prison.Felton was not charged with using the weapon in a threatening manner, which would have created other legal complications for him.

Boyar issued a six-month order of protection for Felton’s wife, warning Felton that ‘‘you can have no contact whatsoever.’’ Felton said nothing during the proceedings. His lawyer, Jim Walden, said Felton had ‘‘no interest in having contact’’ with his wife.

Moments later, Felton walked out of court after posting a $25,000 bond.‘‘No comment,’’ he said to a scrum of reporters and photographers who followed him to the front of the courthouse, where he climbed into a Cadillac Escalade.Felton is expected to be with the Knicks when they visit the Miami Heat on Thursday. The Knicks declined to comment on his arrest.

Felton was ordered to appear in court again June 2 to face a possible felony indictment. He waived the usual statutory time limit for prosecutors to present the case to a grand jury, a common tactic when defendants want to negotiate with prosecutors over a possible plea bargain.

Because he has no prior felony offenses, Felton could avoid jail time even if convicted of both charges. Felton had purchased the gun legally while living in North Carolina, the police said, but it was unlicensed in New York.

The Knicks are no strangers to drama this season. Their general manager was fired days before the start of training camp. Carmelo Anthony announced his intention to pursue free agency before they played their first game.

Coach Mike Woodson has faced questions about his job security since December.Amid all the booing and the losing, Felton has plodded along, chronically underperforming while battling a series of injuries. It was only a week ago that the Knicks, dissatisfied with Felton’s play, tried to send him to another team before the NBA trade deadline. They were unable to do so because few, if any, teams wanted him - or his contract, which runs through 2015-16.

Felton is averaging 10.4 points and six assists per game while shooting 40.3 percent from field.

Earlier this month, he acknowledged that personal issues had become a distraction, although he declined to elaborate. It was later reported that his wife had filed for divorce; Felton was asked about it Friday, when the Knicks were in Florida to play the Orlando Magic.

‘‘Yeah, that’s my personal life,’’ he said. ‘‘I don’t discuss that. I mean, it’s your life. When you’re going through certain things in life, it’s on your mind no matter what.’’

According to the terms of the collective bargaining agreement between the players union and the NBA, a player convicted of a violent felony, or who pleads guilty to one, will be subject to no less than a 10-game suspension, as well as league-mandated counseling sessions. A violent felony, in this instance, is defined as the use or threat of a deadly weapon.

The league also reserves the right to pursue its own investigation, although it tends to wait for court proceedings to play out before taking disciplinary action. In these situations, a player cannot be punished twice for the same transgression, so the league typically metes out punishment instead of the team.

An NBA spokesman said they were monitoring the situation involving Felton.

The collective bargaining agreement allows for the termination of a contract only ‘‘if the egregious nature of the act or conduct is so lacking in justification’’ that it warrants that type of penalty. That is a high hurdle to clear. Contracts are nearly impossible to void, unless the player winds up in prison and cannot fulfill his obligations.

Felton originally joined the Knicks for the 2010-11 season and generally played well before being traded to Denver with other players in the deal that brought Anthony to New York.

Felton then played for Portland in the lockout-abbreviated 2011-12 season and was admittedly not in top shape, which made him the target of criticism. Then, in a surprising move, he rejoined the Knicks in 2012 after the Knicks’ front office decided to let the immensely popular Jeremy Lin depart to the Houston Rockets with a free-agent contract it did not want to match.That left an opening at point guard, and Felton was brought in to fill it. He received a three-year, $10 million deal with a $4.5 million player option for 2015-16.

As he did in 2010-11, Felton played well for much of last season and helped the Knicks to a 54-28 record, their best mark in nearly two decades. But this season has gone in the opposite direction, with the Knicks now burdened with a 21-36 record that will make it difficult for them to qualify for the playoffs.

Felton’s arrest conjured memories of the trouble that Plaxico Burress created for himself in November 2008 when a loaded pistol he was carrying in the pocket of his jeans accidentally went off while he was in a Manhattan nightclub.

Burress, a wide receiver for the New York Giants at the time, ended up with a gunshot wound in his leg. He was subsequently indicted on charges of criminal possession of handgun and reckless endangerment. He accepted a plea deal in August 2009 that carried a two-year prison sentence, which he served.On Tuesday, news of Felton’s arrest reverberated through the NBA.

In Los Angeles, Brooklyn Nets guard Deron Williams, a gun owner, told reporters at a team practice that he was well aware of New York’s stringent gun laws.‘‘I got my license to carry in like 26 states, but I’m not bringing a gun to New York City,’’ he said. ‘‘I know better than that.’’

New York Times