Revere Police Officer Daniel Talbot was “murdered by a man with a purpose and a plan,” the top homicide prosecutor in Suffolk County told a Superior Court jury today at the start of his alleged killer’s murder trial.

“In the early morning hours of Sept. 29, 2007, the paths of two men crossed for an instant with tragic results,” Assistant District Attorney Edmond Zabin told the jury that will weigh the fate of the alleged gunman, ROBERT IACOVIELLO, Jr. (D.O.B. 6/19/87), and his alleged accessory, JAMES HEANG (D.O.B. 6/19/90).

The 30-year-old Talbot, Zabin said, was off-duty and joined by his fiancée and three Revere Police colleagues at the baseball diamond behind Revere High School. Among the officers – all of them off-duty – was Talbot’s childhood friend, Officer William Soto.

It was there, Zabin said, that Iacoviello shot Talbot to death with a 9mm handgun – the 30-year-old Gulf War veteran “ambushed,” the prosecutor told jurors, “by a man who thought they were members of a rival gang. Officer Talbot was a mistaken target of a deliberate act.”

Talbot and his fellow officers had spent part of the day at a shooting range, qualifying with their department-issued firearms. Afterwards, they went to a Revere restaurant, where they met up with Talbot’s fiancée.

As the night grew later, they left the restaurant and “went to the place where Dan Talbot and Billy Soto used to hang out – the bleachers.”

The group had not been there long, Zabin said, when DEREK LODIE (D.O.B. 1/2/90) arrived at the scene. Lodie was an alleged member of a group known as “B’Way,” aligned with the Bloods street gang.

“As Lodie walked through the park, Officer Talbot made a comment,” Zabin said. “‘There goes a gangster.’”

Lodie “kept walking,” Zabin said, “but he didn’t let it go. To him, it was a challenge. To him, it was time to call the cavalry.”

Lodie pleaded guilty in October to setting Talbot’s homicide in motion, using his cell phone to summon armed allies to the field. Those allies – allegedly including Iacoviello – retrieved a firearm and raced to meet Lodie, who now walked from the nearby parking lot back into the park.

“You think you’re so tough, we’re going to show you,” he said, according to Zabin.

Knowing that Iacoviello and others were on their way with a gun, Lodie continued to bait Talbot, “drawing him into the darkness, drawing him towards the parking lot,” Zabin said.

“What Talbot and Soto didn’t know was that, in the darkness of that parking lot, coming from True Street, was an armed gunman,” Zabin said.

“As soon as the defendant entered the park, he fired at least two times,” Zabin said. One of those shots struck Talbot in the head, mortally wounding him. Soto fired twice but did not strike his target.

“By the time he got his gun out, there was nobody there,” the prosecutor said.

As Talbot’s fiancée called for help, the assailants fled the scene.

“They thought they shot a gang member,” Zabin said, “but they soon found out they had killed a police officer.”

In the days that followed, Iacoviello allegedly asked friends and associates to assist him in creating an alibi.

“The defendant James Heang took the murder weapon and broke it into pieces,” Zabin said. [Iacoviello’s] girlfriend, GIA NAGY (D.O.B. 6/2/90), discarded them.”

Nagy pleaded guilty last month. Like Lodie, she is serving a state prison term as an accessory to Talbot’s homicide.

Zabin said that Massachusetts State Police homicide detectives took over the investigation in the aftermath of Talbot’s homicide, undertaking a “thorough and independent” effort to develop, gather, scrutinize, and document evidence.

“They investigated the perpetrator,” he said. “They investigated the police. You will see the fruits of that independent investigation. We will present to you a complete investigation.”

Zabin also urged jurors not to be distracted by the actions and reactions of those not involved in Talbot’s murder.

“Keep your eye on the ball and remember why you’re here,” he said to the 16-member panel and pointing toward Iacoviello. “A police officer is dead and that man killed him.”

Zabin is prosecuting the case with Assistant District Attorney Edward Krippendorf. Iacoviello is represented by attorney Peter Krupp and Heang by attorney Willie Davis. Judge Patrick Brady is presiding over the case in courtroom 815 of the Suffolk County Courthouse.

The trial is expected to last about three weeks.