The man was discovered unresponsive in Tower Hamlets Cemetery Park in Southern Grove.
A post-mortem examination on Thursday found the cause of death to have been blunt force trauma to the head.
Searches are ongoing at both the murder scene and an address in Tower Hamlets. The victim has yet to be named by the authorities.
Detective Superintendent Pete Wallis, of the Met’s Specialist Crime Command, said: “The investigation into this death is being conducted by homicide detectives who are committed to discovering the circumstances of this incident.
“This arrest marks a significant development and officers have been working around the clock to bring justice to the victim and his family.
“Throughout our enquiries we have spoken to numerous members of the public, conducted house to house in the area and have trawled hours of CCTV, but we still need to hear from anyone who was in the area around Cemetery Park during the early hours of August 16
“The victim was attacked in what is suspected to be a homophobically motivated attack, but we remain open minded.
“The investigation team are working with the LGBT Advisory Group. This investigation is fast-paced, I would ask that people are aware of their surroundings and are vigilant in their personal safety.”
“The concern caused by the discovery of a body in these circumstances sends ripples throughout the community and may result in people discussing information that they have.
“I urge anyone who hears anything relating to this murder to get in touch without delay.”
Superintendent Mike Hamer, of the Met’s Central East Leadership and Support, said: “We are shocked by the nature of this horrendous and brutal attack. Our thoughts are with the victim’s family and friends at this time.
“We, and our partners within Tower Hamlets, are supporting the investigation team and are absolutely committed to bring the offenders to justice.
“Currently an extensive crime scene remains in place and police search teams are meticulously examining the cemetery grounds for forensic opportunities.
“The community can expect increased police presence in the area by way of reassurance and I would ask anyone with information to come forward.”
Anyone with information is asked to call the Incident Room direct on 0208 345 3865, call 101, or Tweet @MetCC quoting 1277/16. Alternatively, you can give information by following this link.