CAPE MAY COURT HOUSE — College friends Vincent DeSario, Colton Finney and Michael Maglione laughed and joked around after Maglione tripped on their way to the Wildwood Boardwalk.

But the laughter that day in May 2010 was short lived after a passing stranger — identified by authorities as 31-year-old Wildwood resident Alberto Martinez — asked them, “Are you laughing at me?”

DeSario tried to explain they were not, but before he could finish, the man grabbed a baseball bat and swung it at DeSario’s head, striking DeSario so hard witnesses described the sound as being “like a gunshot.”

Finney testified as Martinez’s murder trial began Monday that the attacker hit the 19-year-old “as hard as you can swing.”

“Like you’re trying to hit a homerun?” asked First Assistant Prosecutor Rob Johnson.

“Absolutely,” Finney replied.

DeSario fell to the ground and the man, Maglione testified, made one more remark.

“‘Now you know or now you learned not to laugh at me,’” Maglione said.

Witnesses to the attack were among the first to testify Monday.

DeSario, of Edison, was a student at Middlesex County College and was staying in Wildwood while taking part in a collegiate golf tournament.

The day of the attack, May 10, 2010, the group had played a round of golf and after dinner decided to walk across Atlantic Avenue and down Oak Avenue to the nearby Boardwalk.

Finney said the man he would later identify as Martinez was riding his bicycle toward them as they began to laugh.

The man then asked if they were laughing at him, left his bike and grabbed a bat, what Finney described as a Major League Baseball-type bat, that was attached to the side of the bike.

“He was walking towards us and slowly raising it towards his shoulders as if he was about to hit a baseball,” Finney said.

The blow struck DeSario on the left temple, Finney said. DeSario fell down and was motionless as “blood starts pouring out.”

The attack caught the attention of passers-by Angela Alexander and Paul Conway as they walked down Atlantic Avenue.

The attacker, Alexander said, was a Hispanic or light-skinned black man, but she could not mistake his hat.

“I hate the Yankees. It’s the only reason I even noticed the hat,” she said.

The other witnesses likewise described a Yankees hat. Others also noticed jeans, a light gray sweatshirt or hoodie and a jacket, all details police would learn as they attempted to locate the attacker.

They also described the bicycle, white with a fishing rod and tackle box or some other storage box attached to the back.

Minutes after the attack a man matching the general description was found on New Jersey Avenue and Finney, Maglione and Conway each identified him as the suspect.

Martinez, who lived in Wildwood and who has been described by police and attorneys as homeless and/or transient at the time of the attack, was arrested that night.

While the police looked for the suspect, DeSario’s friends called for help.

“It seemed very unprovoked to me. It seemed very random,” Conway said of what he saw from across the street.

Conway said the sound was “like a gunshot.” He added, “The audible sound of that crack. I knew it was bad.

In his opening statement, Johnson said DeSario never regained consciousness.

“It was a devastating blow to the head of Vincent DeSario,” Johnson told the judge.

John DeSario, Vincent’s father, was the day’s first witness. He recalled receiving a call around 9 p.m. that night from Wildwood Detective Sgt. Ken Gallagher.

John DeSario said he was told his son had been assaulted. His reaction, he explained, was one of “stunned disbelief.”

He was told, “Get down here as fast as you can. He’s in critical condition.”

Initially, DeSario said, he was told his son was “not going to make it through the night.”

But Vincent survived two more weeks, eventually succumbing to his injuries on May 24, 2010, at AtlantiCare Regional Medical Center in Atlantic City.

“He just passed away,” John DeSario said as about two dozen friends and family members, many wearing badges with Vincent’s picture on them, listened.

During cross-examination of the witnesses from the scene, defense attorney Stephen Patrick focused on the discrepancies in the witness statements with different descriptions of the hat, clothing and the man’s ethnicity.

Wildwood police officers Christopher Chobert and Kevin Flanigan also testified about their response and the witness identifications.

Patrick noted that some initial descriptions had the assailant as a black male wearing a white Yankees cap. The hat was actually black and gold.

The weapon has also never been found.

During his opening, Johnson said Martinez deliberately struck DeSario and then took steps to conceal the crime by changing his direction of travel, putting up the hood on his sweatshirt and getting rid of the bat.

Johnson said those actions defeat the defense argument that Martinez was not sane at the time. Instead, he said, they demonstrated Martinez knew right from wrong.

Patrick gave a brief opening in which he told Superior Court Judge Patricia Wild that the fact that an incident occurred did not automatically constitute murder, but perhaps some lesser offense.

And, he said, his client is a paranoid schizophrenic and that a psychiatrist will testify he is insane.

The trial will resume today.

There is no jury because Martinez requested a bench trial, meaning Wild will decide the outcome of the case.

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