A Toronto homicide detective says a 37-year-old tech CEO was completely defenceless when he was shot to death in upscale Yorkville on Monday night.

Matthew Staikos was shot to death at close range as he was walking on Yorkville Avenue around 11:30 p.m. on Monday. Police say a lone gunman approached Staikos from behind, opened fire, then fled the area in a silver-coloured four-door Mercedes.

Det. Omar Khan called the killing an "unprovoked attack on a defenceless man" at a news conference where he also released surveillance video of the getaway car.

Surveillance Video: If you can ID suspect or vehicle involved in the homicide shooting death of Matthew Staikos on Monday May 28, 2018 11:30pm in Yorkville area of Toronto contact Detective Omar Khan 416-808-7400 or Omar.Khan@TorontoPolice.on.ca Anonymous tips 1-800-222-8477 <a href="https://t.co/Ec5glgSnRM">pic.twitter.com/Ec5glgSnRM</a> —@TPSHomicide

Khan told reporters the motive in this case is still unclear, but that the shooter clearly intended to shoot Staikos.

He said the victim's family is struggling with the loss, and cannot grasp why this happened.

Khan says investigators are trying to put that together, and hinted they have more information than was released on Friday. "We have collected a lot of video," he said.

Det. Omar Khan playing security footage prior to Monday’s shooting in Yorkville, says shooter purposefully shot but won’t say “targetted” Matthew Staikos <a href="https://twitter.com/CBCToronto?ref_src=twsrc%5Etfw">@CBCToronto</a> <a href="https://t.co/0qVYtTaceT">pic.twitter.com/0qVYtTaceT</a> —@AdrianCheungCBC

Victim sold 1st company to BlackBerry

Staikos​ was a tech entrepreneur who studied computer engineering at the University of Toronto.

In 2003, he co-founded Torch Mobile, which was acquired by BlackBerry in 2009. He went on to work at BlackBerry for four years.

In the days since his death, a number of his colleagues in the city's tech community have expressed their condolences online.

Matt Staikos and his brother <a href="https://twitter.com/grstaikos?ref_src=twsrc%5Etfw">@grstaikos</a> were a badly needed injection of new tech and outside the box thinking to <a href="https://twitter.com/TeamBlackBerry?ref_src=twsrc%5Etfw">@TeamBlackBerry</a> I remember flying to SF and in 5hrs learning everything I needed to know about Webkit. RIP Matt. —@j3ff_M I only ran into Matt a few times after we both left RIM. It had been years since I last saw him. Hearing the news today, I went back and checked our old correspondence - our DMs are just endless attempts to schedule a meetup. I truly regret not doing more to make it happen. —@tron

In 2015, Staikos​ became the CEO of Vleepo, a messaging app that was being developed in Greece. Vleepo had launched for Apple's iOS devices in 2017, but is no longer available on the app store.

Both Staikos' and Vleepo's social media accounts went quiet in late 2017, with no new public posts since December on Facebook, Twitter or Instagram.

Staikos is also being mourned in the Greek-Canadian community, with Dimitris Azemopoulos, the ambassador of Greece to Canada, posting on Facebook about his grief at losing a "wonderful man and friend."

Staikos's funeral is set to be held in Belleville, Ont., on Saturday, according to an online notice.