The Florida inmate who cops say was communicating with the wife of “Ghost Adventures” star Aaron Goodwin as part of her alleged murder-for-hire plot is a convicted killer himself … TMZ has learned.

Police say Aaron’s wife, Victoria Goodwin, hatched a plan to off her husband to get out of her marriage … and she allegedly enlisted a prisoner named Grant Amato to help her see the diabolical plan through.

Well, we did some digging and discovered Amato is serving a life sentence for a triple murder involving his family. A former nurse, Amato was found guilty in 2019 of fatally shooting his father, mother and brother in their Florida home.

Cops say Victoria told them she first learned about Amato in a true-crime documentary and became pen pals with him while he was behind bars.

Police say Victoria told Amato she wanted to kill Aaron and provided information about Aaron’s location and set times in California while he was filming “Ghost Adventures” with Zak Bagans.

Cops say Aaron’s wife and Amato set aside $11,515 to pay the alleged hitman … and Amato messaged someone about the alleged plot, texting them … “He’s asleep right now in the hotel room … I need to know what’s going on. Can I get an update. Was it done?”

The murder never happened … but as we first reported, Victoria was arrested last week and charged with solicitation to commit murder and conspiracy to commit murder.

Aaron told us he was blindsided by the developments, and now he’s getting court-ordered protection from her. According to new legal docs, obtained by TMZ, Victoria is barred from contacting Aaron for the next 3 months.

TMZ also spoke with Amato’s former defense attorney, Jared Shapiro, who repped him in his triple murder case, which was the subject of a Paramount+ documentary, “CTRL+ALT+DESIRE.”

Shapiro described Amato as a “normal person” until he committed the homicides, adding that he has a calm demeanor and nothing really phases him, including jail.

Shapiro also says Amato believes he’s always the smartest person in the room and comes off as “arrogantly intelligent.”

Furthermore, Shapiro says Amato enjoys the spotlight and was speaking to Paramount+ producers about the documentary while he was in jail for the murders.

What’s more, Shapiro says he’s not surprised Amato was allegedly involved in the murder-for-hire plot because he likes the attention and wants to feel useful.