Vancouver police are warning the public to be cautious after two seemingly random attacks in Stanley Park in recent months.

The first attack occurred in November, and left an elderly man with serious injuries. The man was found in distress at approximately 2 a.m. on Nov. 16, 2016.

Police have been investigating his case for months, but said Tuesday night that they have not been able to identify a suspect or a motive. The man remains in hospital.

The second was fatal, and occurred 11 weeks after the elderly man's assault. Lubo Kunik, 61, was walking by himself on the park's seawall on Feb. 1 when he was attacked and killed.

His body was discovered by a man walking his dog shortly before 11 p.m. Police have yet to identify a motive or suspect in that case as well.

"This is something which is terrible. It could be your brother, my brother, my son, your son, mom, dad, anybody," Kunik's friend Pavol Gorel told CTV News on Wednesday.

He also questioned why it took police nearly a week to put out a warning to the public, saying it should have been done right away.

Investigators working on Kunik's case questioned a person of interest the night of the homicide, but Const. Jason Doucette confirmed Tuesday the man has since been released. He remains a person of interest in the case.

"While there is no evidence to directly link these two serious incidents, we cannot confirm the events are not related," Doucette said.

"In the absence of suspect information and motive, we feel it’s necessary to issue a public warning to alert people who may be in Stanley Park at night to use extra caution."

Doucette said police have increased their patrols in the park, and have been in contact with members of the Vancouver Park Board about the investigations.

Anyone visiting Stanley Park at night is advised not to go alone, and to report suspicious behaviour immediately to 911.

Police ask anyone with information on either attack to call them at 604-717-2500 or Crime Stoppers at 1-800-222-8477 (TIPS).

With files from CTV Vancouver's Scott Roberts