For killing a teen girl, Miami man gets just 13 years in prison. It’s his second murder.

For his first murder, shooting a woman to death in the 1980s, Armando Botell served less than 10 years in prison.

The 70-year-old Miami man won’t spend much more time in prison for his second murder.

Under a plea deal struck Thursday, Botell pleaded guilty to murdering 17-year-old Romina Fernandez, then dumping her body in a Sweetwater trash bin and setting her ablaze in October 2014.

Botell will serve 13 years behind bars, plus two years of house arrest and eight years of probation. With credit for the time he’s already served — and if he behaves behind bars — he could be released in five years or so.

The plea deal was struck with the blessing of Fernandez’s parents, who appeared in court Thursday but declined to make a statement to the judge. “There’s been quite a bit of emotional drain on the next of kin,” prosecutor Sonali Desai told the court.

The plea deal, however, did not sit well with the homicide investigators who arrested Botell.

“I’m disappointed. We would have won at trial. He deserves to be in prison for life,” said Miami-Dade Detective Juan Segovia.

The guilty plea came four years after Botell was arrested for the strangulation murder of Romina, a troubled teenager who had dropped out of school and had been taking drugs from the older man.

Andrea Perez holds a photo of her daughter, Romina Fernandez, who was found murdered and burned in a Sweetwater dumpster in 2014. Hector Gabino el nuevo herald

Miami-Dade homicide detectives put together a circumstantial case against Botell, who was described as having been obsessed with the teen for months. For at least two years, investigators believed, Botell had plied her with drugs. He had sex with her, kept nude photos of her on his phone and grew fixated on her life.

“He was obsessed. He was sick. It was an obsession he had with her,” one of Botell’s friends told Miami-Dade detectives. The friend said Botell had even paid him to follow her around.

Detectives relied on cellphone records that placed Fernandez’s phone at Botell’s home. Hours after her phone was shut off, video surveillance showed the Mercedes ML350 believed driven by Botell arriving and departing from the trash bin where her body was found.

The Miami-Dade State Attorney’s office did not immediately say why 13 years was the appropriate sentence. Robert Finlay, Botell’s defense attorney, said it was a good deal for his client because the risk of going to trial was great.

“His being a 70-year-old man accused of killing a 17-year-old girl is difficult emotionally for jurors,” Finlay said. “There’s a lot of underlying prejudice about older people being with younger people. He’s a good man underneath it all. He’s just had trouble with relationships.”

Botell had killed one of his love interests before.

He served less than 10 years in prison for murdering his girlfriend, Dilia Padron, in December 1980. He confessed to shooting her to death in the kitchen of their home because he believed she had cheated on him.

Her daughter appeared in court on Thursday, although she did not address the court. Her lawyer, George Pallas, said the family did not agree with the sentence in either case.

“Thirteen years for a serial killer is not adequate,” Pallas said. “It’s outrageous.”