It was unusual enough when Baltimore housing officials had to get a search warrant to gain entry to a Canton rowhouse where they believed illegal renovations were occurring. But the owner's son had barred inspectors, and neighbors were complaining of work that was noisy, substantial and ongoing.

Then inspectors went inside and were shocked to find that the three-story home in the 2100 block of Cambridge Street had been gutted. Not only had the owner's son failed to pull required building permits, the city alleged in a lawsuit, but the work was so shoddy that the house had to be condemned.

The discoveries in October, combined with a history of illegal construction at the house, spurred housing officials to take another rare step: They filed criminal charges against the owner's 54-year-old son, Martin Pozoulakis. And now, If convicted, he could receive the rarest of punishments in such cases — jail time.

City officials say the case shows that when safety is at stake and other enforcement measures fall short, they aren't afraid to throw you behind bars for breaking the rules.

"The purpose of that action is to punish the behavior," said Deputy Housing Commissioner Michael Braverman. "It really was out of the ordinary. Much less drastic methods could be used to address the majority of the work that goes on without a permit."

In most cases, even major permit violations typically result in citations and accompanying fines. But in 2006, amid the housing rehab frenzy, the City Council added a jail term for the misdemeanor crime of doing work without a permit. A year later the term was modified to 90 days.

The threat of jail time was meant to deter serial violators who viewed fines as a cost of doing business. Officials say the enhanced penalty is pursued only a few times a year, and they could point to just one case in which a violator actually got locked up.

CityCouncilman James B. Kraft, whose Southeast Baltimore district includes Canton, pushed to add the 90-day jail penalty to the books. "We need to have that additional leverage for the really bad guys," he said, speaking generally. "It's not a tool you want to use indiscriminately."

Pozoulakis, who lives in Ellicott City, told The Baltimore Sun that the recent events involving his mother's home were an "unfortunate thing" that could have been handled differently. And in an email to city officials he defended his actions. He declined to discuss details of his case further, on the advice of his lawyer.

"That's a private matter between Mr. Pozoulakis and the city," said his lawyer, Bernadette M. Hunton. Attorney Anthony P. Palaigos, who represents Pozoulakis' 88-year-old mother, Millie, also declined to comment.

In interviews and emails to the city, neighbors make clear that the renovations have caused considerable worry and frustration.

"It was pretty crazy over there," next-door neighbor Terri Dwyer said recently, days before finalizing the sale of her house, which she bought in 2000. Her growing family — not the dispute — prompted her move, she said, though having a "condemned" sign next door didn't help her home's curb appeal.

Dwyer said her concerns ranged from safety to what she perceived as Pozoulakis' effort to carve his mother's home into apartments. "With our houses being connected, if the electric wiring is wrong and you have a fire, we're affected, too," she said.

Cambridge Street runs parallel to Boston Street, near the Canton waterfront. Both sides of the 2100 block are lined with brick rowhouses, many valued at well above $200,000. The Pozoulakis family has deep roots on the block. Millie Pozoulakis and her now-deceased husband, Chris, bought the house in 1971, land records show, decades before the area's gentrification.

Dwyer said she never had a problem with the family until Martin Pozoulakis built an illegal one-story rear addition in 2009.

Pozoulakis failed to obtain permits for that addition, according to the city. Braverman said the housing agency was on the verge of sending a wrecking crew to dismantle the addition when Pozoulakis finally relented, converting it to an open-air porch.

Dwyer hoped the neighborhood drama had ended. Then last year she realized Pozoulakis was building an exterior staircase that ended inches from her children's second-floor bedroom window.

"That really bothered me just because of the proximity — someone could break in," Dwyer said.

Pozoulakis had applied for a permit. But his application called for replacing and repairing rotted wood on an existing staircase. Dwyer, echoed by other neighbors, insists that there hadn't been a staircase there since at least 2000. There was just a metal platform outside a second-floor window.