l found Piotr asleep under the willow tree in Wandle Park. It was an afternoon in July, and we couldn’t return to the hostel yet. He said he’d dreamed that old green men were talking to him, and told him where to get some money.

I didn’t see Piotr the next day, and the day after, I heard he’d moved out.

A week passed, and then a BMW honked at me as I walked along the high street. Piotr was driving. He said he’d had a win on the horses; did I want any money? I’d always been his friend. Something scared me, so I laughed and said: no thanks. He told me to ring him if I changed my mind.

After that, someone started tying ribbons to the willow branches.

I saw Piotr lying there again in September, when it was raining. He said he owned a semi in Carshalton now but still came here ‘for inspiration.’

Piotr’s probation officer was strangled in her flat, with no sign of anyone entering or leaving. He’d always hated her.

The council cut the ribbons off the willow tree, but more kept appearing. Now and again I’d see Piotr’s BMW near the park.

It came on the news that Piotr was wanted by the police for murdering his girlfriend. She was an ex-model. 

The next day, a dog-walker heard Piotr scream from under the willow tree: “You made me do it!” When she got there, Piotr lay on the ground, strangled.