A man accused of chopping up his friend's body and dumping his severed head in an apartment block's recycling bin had previously started a bloody fight at his gym, it has emerged.

Carlos Colina, 32, is being held on $1 million bail after pleading not guilty to aggravated assault and battery and improper disposal of a human body in Cambridge, Massachusetts on Monday.

The remains of Jonathan Camilien, 26 , including a torso and limbs, were found in a duffel bag near the campus of Massachusetts Institute of Technology on Saturday morning before his head was found in Colina's apartment building across the street, according to the police report.

Now the Boston Herald has unearthed police reports and witness accounts showing Colina had intimidated fellow gym users and even fought them before being thrown out.

Accused: Carlos Colina is pictured at his arraignment in Cambridge, Massachusetts on Monday after human body parts were discovered in a duffel bag and a head was found in his building's recycling bin

Colina previously worked out at the Cambridge Athletic Club but was kicked out following a fight over gym equipment on November 24.

A witness told the Herald how Colina started punching a much smaller man all over his body as the man unsuccessfully tried to fight back. He suffered bloody cuts to his head, the witness said.

'The trainers broke the fight up,' he said. 'Carlos gets up and starts walking away, yelling, "I'm a beast! I'm a beast!’ like he was proud of himself.'

The victim suffered broken ribs in the attack, WHDH reported.

Colina has an outstanding assault and battery case pending against him from the fight.

The witness said that before the November incident, Colina stood and glared at other gym users if they were using gym equipment he wanted.

'Intimidating': Colina, pictured in photos he posted to Facebook, also has an outstanding assault and battery case pending against him after he allegedly attacked a fellow gym user last November

'Threats': A witness said Colina had also intimidated other gym users when he wanted to use equipment

Colina is believed to have known his alleged victim; he is friends with his younger brother, Christopher Camilien, on Facebook. The two brothers lived together in Somerville.

Middlesex District Attorney Marian Ryan said Camilien's death is considered a homicide, even though Colina has not been charged with murder. She said analysis of evidence and more information from the medical examiner are needed to determine if additional charges are warranted.

'We are not seeking anyone else in connection with the discovery of these human remains,' she said.

No motive has been released.

Colina and Camilien were last seen returning to the building just after 11pm on Friday, according to the investigation, and a neighbor reported hearing an argument coming from the apartment.

Colina was seen in surveillance video from nearby Biogen offices exiting the apartment building at about 4.15am on Saturday carrying a duffel bag, authorities said.

Scene: A vacuum could be heard inside his building, pictured, after police discovered the victim's head

Probe: Police stand by where the remains of Jonathan Camilien were discovered in Cambridge on Saturday

He returned to the apartment building empty handed.

A saw, rope and cleaning supplies were found in Colina's apartment, which is located one block from the Cambridge Police Department.

He also had wounds on his face and neck and a vacuum could be heard during the search when police discovered the victim's head, according to theBoston Globe.

Defense attorney John Cunha Jr. called it a sensational case.

'Obviously the circumstances of the case are sensational enough,' he said. 'I'm not going to exacerbate it.'