BOSTON (CBS) – Thieves have a new target. The number of bike thefts is soaring across the state.

Surveillance video from the MBTA shows how brazen these crooks have become. One clip shows a young man not only stealing a bike, but also taking parts from other bikes. All of this takes place at the Forest Hills station in the middle of the day.

Thefts in Brookline are up 40% year to date, according to Lieutenant Phil Harrington.

Thieves are becoming more brazen. ‘They are walking into people’s back yards. They are taking them out of garages. They are also going up to front porches,” explained Harrington.

The I-Team found thefts up 33% in Somerville and 13% in Cambridge so far this year.

Julia Featheringill was stunned when her $500 bike was ripped off in Cambridge. It happened at three o’clock in the afternoon. “I almost couldn’t believe it,” she says, “and then my sort of daze turned into anger.”

William Raymund learned a hard lesson about locking his bike to a wooden railing on his back porch in Mission Hill. It was stolen in the middle of the night.

“To know that somebody came onto your personal property, violated your personal space can be emotionally challenging,” explained Raymund.

The I-Team found case after case of bikes being stolen across the region. Two weeks ago a bike was stolen on Beacon Hill. Just hours after the police report was filed, that bike was found for sale on Craigslist.

But this trend isn’t just about reselling hot bikes.

“Some people are just stealing them for scrap, because scrap metal prices are extremely high right now,” said Deputy Chief Robert Lenehan of the MBTA police.

With increased surveillance and suspects in mind, the T police is cracking down on bike thieves. They want to not only protect commuters, but they also realize stolen bikes can be used to commit other crimes.

For example, Lenehan said thieves, “would set out for the day when they wanted to steal handbags, and they would steal a bike as a getaway.”

In Brookline, police have trailers filled with abandoned bikes. They believe gangs are stealing everything they can find in a neighborhood, and then dumping the ones that don’t meet their standards.

“The last two instances where we have had arrests actually involved groups,” added Harrington.

Police suggest bikers use a U-Lock, and not one made of cable. The latter can easily be cut with a cheap tool.

They also say bikers should register their bikes. That way police have a way to reunite them with their bike if it is found.

Police tell the I-Team they believe there are many more cases of theft than they know about. Stolen bikes are often not reported because there are no insurance claims to be filed.