Two years ago, Needham High School graduate Nicholas Burdett traveled to Miami Beach with his girlfriend to celebrate his 25th birthday. After a fight with her over a tattoo he wanted to get, Burdett left their hotel room and was later shot and killed by an off-duty sheriff’s deputy on Miami Beach.

This week, the Miami-Dade state attorney said the shooting was justified, saying Burdett threatened the off-duty deputy and the deputy’s girlfriend with a knife and demanded money. A toxicology report said Burdett had been drinking and had ingested some prescription medications.

The off-duty Palm Beach County sheriff’s deputy, Justin Clayton, told investigators that he fired at Burdett because he “didn’t know any other way to make this stop, make this end. . . . I was afraid I was going to die.’’

The Burdetts’ family lawyer rejected the findings yesterday.

“That is such a fairy tale,’’ responded Timothy Burke, the Burdetts’ lawyer.

“They withheld this information for two years because they were afraid we would file a lawsuit,’’ he said yesterday. “This is a calculated, intentional move on their part to prevent us from any further discovery in this case prior to the statute of limitations expiring.’’

Abbe Rifkin, Miami-Dade assistant state attorney who handled the case, dismissed the criticism of her “closeout’’ report.

“The delay in final closeout should have no bearing on an experienced attorney doing his own investigating and filing whatever lawsuit he deemed appropriate, regardless of the outcome of the criminal investigation,’’ she said yesterday by phone.

David Burdett, Nicholas’s father, declined to comment yesterday but he and his wife coincidentally sat down for an interview Monday with the Globe to discuss the delay in closing the investigation. They had not seen the closeout memo but knew of the allegations against their son.

“It’s something you can’t fathom him doing,’’ said Burdett. “He’s got plenty of money. It doesn’t make any sense.’’

Rifkin wrote that the actions of Clayton were “lawful, justifiable, and not actionable.’’

Burdett, a Springfield College graduate who was working off and on in home construction, was vacationing with his girlfriend, Linna Hor, who was 23, on the night of the 2009 shooting.

According to Rifkin, Hor told police that she and Burdett had argued the evening of March 16, just hours after arriving in Florida, because Burdett had left a $60 deposit with a tattoo parlor. When police asked Hor why Burdett might have tried to rob someone, she allegedly said, “Perhaps he was trying to get the money he lost on the deposit back,’’ Rifkin wrote.

It was unclear how Burdett would have obtained the knife investigators say was used in the alleged robbery attempt.