WEST MIAMI-DADE, Fla. (WSVN) — Police have arrested a man they had detained earlier as a person of interest in the murder of his longtime roommate in a Miami Beach high-rise.

Thirty-year-old Jonathan Alonso was transported to the Turner Guilford Knight Correctional Center after having been interviewed by Miami Beach Police detectives, Friday. He has been charged with first-degree murder and criminal mischief in the death of his longtime roommate, Lou Piper.

7News cameras captured Alonso becoming angry as he was taken out of the van and into jail. The footage shows the suspect spitting so many times that police had to restrain him and put a mask over his face.

Police said Piper was brutally murdered inside their upscale condominium at 1800 Sunset Harbor Drive, Wednesday. Officials found Piper’s body, approximately 60 years old, Wednesday. However, 7News learned the victim was reportedly dead several days before his body was discovered.

"Lou was a very, very dear friend of mine for nearly 25 years," said Kristin Klein, a longtime friend of the deceased.

Officials found Piper’s body, approximately 60 years old, Wednesday. However, 7News learned the victim was reportedly dead several days before his body was discovered.

It was actually a 7News viewer who spotted Alonso walking a pug at a park near Downtown Miami, Friday afternoon. "I noticed this gentleman sitting on a bench acting very erratically," said the witness, who asked not to be identified or show his face on camera.

The witness said he recognized Alonso because he had seen surveillance video aired on "7News at Noon" showing the person of interest and what appeared to be the same dog in an elevator. The footage also showed Alonso leaving the condo on Wednesday. "I looked down and I saw the dog and kind of put two plus two together after seeing the news. I asked the folks from the boat behind me if he was with them just to make sure before I said, ‘I think I’m going to call the police.’"

The witness contacted authorities, and Miami Police came to take Alonso into custody. "I had a pretty strong suspicion that it was him because of the dog," said the witness.

Alonso and Piper had been involved in domestic issues, including a lawsuit by the victim. Court papers show Piper was trying to get his roommate kicked out of the condo.

Co-workers apparently hadn’t heard from the victim in several days and became concerned. 7News sources also said that the scene inside the 12th-floor unit was bloody and gruesome.

One building resident said when he was leaving his apartment recently, he noticed a stench that came from the victim’s unit, which suggested that something was horribly wrong.

According to a police report, Alonso was inside the apartment, next to Piper’s decomposing body, when friends came to check on the victim’s well-being on Wednesday. The report further state that Alonso would not let them inside.

A neighbor commented on how surprising the murder is. "We’re all very surprised, horrified and — we don’t know what to say anymore until we find out what really happened."

When asked what she felt when she first heard of her friend’s passing, Klein replied, "Utter shock, utter and complete shock. I think there’s still a lot of disbelief still in the air, and people just scratching their heads, with a big question mark, like, what happened? Why?"

Another neighbor who didn’t want to show his face on camera said he knew the victim, and he believes the victim may have known his attacker. "It’s certainly shocking," he said. "It’s a very nice building. People are very friendly actually, and it’s very well-run, so I’m just astounded. I presume the people knew each other that were involved, and it’s not something random."

Longtime friends of Alonso and Piper said the two had lived together for about seven years and described their relationship as tumultuous. "Whoever did this, I hope they bring them to justice, and whatever the law deems as punishment, I hope that person receives it," said Klein.

Homeowners who live in the building received letters from the homeowner’s association that said the situation was an isolated incident, that there is nothing to fear and that the building is safe.

"Anytime you investigate a homicide, which is not normal for Miami Beach, it is going to bring concerns to the community," said Rodriguez. "We do feel this was an isolated incident."

Alonso’s pug was turned over to animal services.

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