Sumanthiran Selvarajoo was arrested a few hours after he allegedly beat Mr Loo Nam Sheng, 64, with an umbrella.

Police said they received a call at 6.40am informing them of an assault at Ang Mo Kio Garden West opposite Ang Mo Kio Community Library. A McDonald's 24-hour restaurant is situated nearby the park.

But paramedics, who arrived at the scene at 7.10am, declared the man dead.

The park in question has seen its fair share of vice activities.

A cleaner at the park, Ng Ah Chue, 69, told The New Paper that the old man that was found murdered used to exercise alone regularly at the park.

He said he remembered the man because he didn't exercise on the running track. Instead, he would take off his slippers to walk on the grass.

Mr Ng also added that the park is a hang-out for glue sniffers. He said since he started working at the park five years ago, he's seen groups of teens pouring glue into a clear plastic bag and start sniffing.

He said they would gather at the park in the afternoon, about 2pm to 3pm, several times a week to sniff glue and get high.

Besides the glue-sniffers, he said the park is also used frequently by joggers for their early morning runs. Elderly residents would also go there to exercise or practise taiji from as early as 5am.