The family of 6-year-old Brandon Holt, the Toms River boy accidentally shot and killed by his 4-year-old neighbor, filed a lawsuit against the younger child's parents.

Brandon Holt of Toms River was shot and killed by his younger neighbor in April 2013. (Facebook)

According to the civil suit, it was the recklessness of Anthony and Melissa Senatore that led to Brandon's death.

Brandon died in April after his playmate grabbed a loaded rifle from inside his own home and fired a shot that hit Brandon in the head.

"It's the grossest case of negligence I've seen in over a decade," said Kevin Parsons, the lawyer representing the Holt family. "There's no way on God's green earth that this 4-year-old child should have been allowed access to, not only a firearm, but a loaded firearm."

Authorities found additional weapons and ammunition in the home following the incident. Anthony Senatore was arrested last month and charged with child endangerment and a disorderly persons offense.

"Mr. Senatore could go to jail for a thousand years, and pay millions and millions of dollars in damages, and it's not going to bring Brandon back," Parsons added. "There's no amount of money that's going to bring Brandon back, but the hope is that outstanding medical bills can be paid. Then whatever is left can hopefully be used in his memory."

The suit was not accompanied by a specific dollar amount.

Greg Gianforcaro, a New Jersey criminal defense attorney, said he expects the matter to be settled out of court.

"I'm not surprised by this lawsuit whatsoever," he said. "(The Holts) are entitled to relief, monetary relief, for the death of their child."

Gianforcaro and Parsons agreed that no case is certain, but it's clear the Holt family has plenty of facts to work with.

A call to Senatore's attorney was not returned.