For more than a decade, 55-year-old Thomas Sawyer slept on the streets of downtown Vancouver.

It was his home, in every sense of the word, and those who knew him say he will be deeply missed for his charm, wit and out-of-this-world knowledge of botany.

"Seeing Tom was part of my regular routine," said former Yaletown resident Richard Hopkins.

"He was a witty, intelligent, charming guy ... he was a cheerful guy and always had a terrible joke to tell."

Hopkins, like so many who knew Sawyer, was gutted to read in the paper yesterday that Sawyer died on Sunday.

Vancouver police say the death is suspicious and are appealing for witnesses to come forward.

Sawyer died of major internal blunt trauma injuries in hospital Sunday morning after a passerby called in a report of a man in distress.

He was found in an alley behind 928 Richards St. at about 1:30 a.m. and police are hoping members of the public can help piece together what happened to him in the hours before he was found.

Hopkins said anyone who knows Yaletown well will likely know Sawyer for he could always be seen selling flowers, joking around with neighbours and having a chat with people who smoked outside.

Judy Graves, Vancouver's tenant assistance co-ordinator, said Sawyer's extensive knowledge of flowers and plants was incredibly impressive.

"He just felt the life of the planet in plants. He knew the names, the nicknames, the common names, the aboriginal names of plants. He knew even the rare plants in Stanley Park and in other parks in the city and knew their medicinal uses," said Graves.

It's believed Sawyer studied botany in university and that he originally came from the U.S.

It's not clear exactly how Sawyer ended up on the streets of Vancouver, but Graves says he once shared with her a traumatic incident that happened to his family that he witnessed and never got over.

"It was so horrifying that I almost think it's unthinkable what he saw," said Graves, who promised Sawyer she would keep the story a secret.

Graves believes Sawyer blamed himself for not being able to prevent the incident and suffered from post-traumatic stress.

He was not an alcoholic and not a drug-addict, she added.

"Some people you know for so long and they become really special to you. Tom was very special to me," said Graves, who treasures a gold mouse pin he once gave her.

Police took the unusual step of naming Sawyer in hopes of contacting his family.

Police said family members came forward Wednesday night.

lsin@theprovince.com