Detectives investigating the murder of Rocky Djelal on Halloween have arrested two men.
Mr Djelal, 38, died from a stab wound following a knife attack in Southwark Park on October 31.
The Met Police said a 46-year-old man was arrested at a south London address on suspicion of murder on Friday.
A second man, aged 34, was arrested at a separate south London address on suspicion of conspiracy to murder.
Police said both men remain in custody.
Mr Djelal was attacked at around lunchtime close to a playground near the Gomm Road entrance of Southwark park.
Despite the efforts of paramedics, he died at the scene.
A post-mortem examination held on November 1 gave his cause of death as a stab wound.
In a statement after the attack, Mr Djelal family's said the father had a "heart of gold" and they were "grief stricken" by their loss.
Police earlier put out a call for potential witnesses of the stabbing to come forward with any information.
Detectives believe that families enjoying a day in the park may have captured the killer on camera while taking photos of videos of their children.
Mr Djelal had convictions for violence and had only been released from prison in July.
He was jailed for six years in 2014 after pleading guilty to conspiracy to cause GBH in the mistaken identity murder of City porter Christopher Foster.
Aytach Lisani, the knifeman who murdered Mr Foster in a revenge attack against the wrong man, was jailed for life with a minimum of 23 years at the Old Bailey.
In 2001, Mr Djelal was cleared of taking part in a brutal Christmas Eve attack on a Turkish asylum seeker which left him permanently brain damaged.