Police have been after him for years: Andrew Zalewski, professional car thief.

But now it seems the 35-year-old Zalewski could finally be heading to a federal penitentiary after a massive York Regional Police investigation forced him into a plea deal that played out in a Newmarket courtroom.

Zalewski pleaded guilty Tuesday to breaking into homes, stealing luxury SUVs, and a conspiracy to steal some $5 million worth of vehicles.

"This was a very, very large-scale investigation," York Regional Police lead investigator Det. Const. Valdy Krawczyk said outside court.

Court was shown walkie-talkies and a police scanner that Zalewski and 29-year-old accomplice Damian Kaleta used in their sophisticated scheme.

The case was sparked in July 2011 after a home was broken into and a vehicle was stolen.

As police began their investigation, Zalewski was driving around Toronto-area neighbourhoods, looking for high-end vehicles. After casing the neighbourhoods, Zalewski broke into homes, stole the keys from plain sight and drove off with the vehicles from the driveways.

Little did he know, by August 2011, police had secretly installed a GPS tracking device on his vehicle, logging his movements as he went from neighbourhood to neighbourhood.

But it wasn't just residential neighbourhoods that Zalewski spent time in.

His car was tracked to the northwest Toronto rail yard where new vehicles and their keys are delivered. Dozens of vehicle keys were stolen, along with their vehicle information numbers (VINs) -- numbers that could be used to track down who bought the vehicles.

Armed with that information, Zalewski and Kaleta need only find the owners' addresses online, drive to their homes and use the stolen key to drive off with the vehicles.

The thieves were so brazen that they broke into a Vaughan home on Sept. 9, 2011 while the owners slept upstairs. In the front hallway, they found the key to the white Lexus SUV parked outside and drove off with the vehicle before parking it in a so-called "cool-off" spot near Wilson Ave. and Avenue Rd.

A police surveillance team followed them. When the Lexus owners reported their SUV missing the next morning, police knew exactly where to find it.

On another occasion, Zalewski broke into a home looking for some keys, but the owners had hidden them upstairs. Zalewski left empty-handed.

The case highlights two measures drivers can take to protect themselves from this sort of crime.

First, never leave your keys in plain sight. Second, if you buy a new vehicle, make sure it comes with two keys, not one.

"There's no reason you should be receiving a vehicle with one key and if you have, please contact your dealership and express your concerns," Krawczyk said.

Aside from the break-in victims, every victim who had their vehicle driven off their driveway had one thing in common: They only received one key from the dealership; the other had been stolen from the rail yard.

When police searched a Toronto storage locker used by Kaleta and Zalewski, they found 99 keys bundled with their corresponding VINs.

There were enough keys to steal some $5 million worth of vehicles.

"I'm feeling pretty good," Krawczyk said. "It's a good day for York Regional Police and the Auto Cargo theft unit."

Zalewski had previously been the target of several other Toronto-area police investigations, including Project Romeo, Project Ave and Project Underground, but never has he faced federal jail time -- until now.

Zalewski's sentencing hearing is set for February.

For his part in the scheme, Kaleta will be sentenced next week.