The man in the video looks to be white and substantial. He walks up to the front of Matt and Summer Gonter's house at 18 N. Ellwood Ave. and splashes a 5-gallon bucket of silver paint on the marble stoop.

The vandalism, caught on the Gonter's security camera just before 3 a.m. on April 5, takes less than five seconds.

The Gonters hope it's the last straw. They say they know who is behind it-a millionaire they regard as a slumlord whose drug-dealing tenants they've been reporting to Baltimore Housing for years, with little to show for it.

Except harassment.

"He's trying to push us out, but it's doing the opposite," Matt says. "We're digging in."

Over the years, the couple has gotten hundreds of unwanted magazine subscriptions. Someone has posted Matt's cell number on abandoned houses and houses advertising suspiciously low rent, so he gets bombarded with calls. Racist emails have been sent under Gonter's name, he says. And last April someone ripped the skylight off their house.

The couple thinks Thomas Karle Jr. is behind it all. On May 15 they told Mayor Stephanie Rawlings-Blake about it as the mayor surveyed the latest damage.

People in a lot of neighborhoods see neighbors get their tires slashed, their windows busted, garbage thrown at their car. The people who get hit are often the type who call 311 to report trash in the alley and 911 to report corner boys slinging gel caps. When they get hit, they usually shut up. If they tell anyone, it's on the condition of anonymity.

Matt and Summer Gonter are speaking up. "I used to report criminal activity to the housing authority," he told a mayoral aid during the May 15 community "COP walk" with the Patterson Park Neighborhood Association. "I think someone leaked my name, so the guy vandalized my house."

Since buying the rowhouse for $275,000 from Patterson Park Community Development Corporation in 2005, Gonter has become known for his activism on property-tax issues and on the federal Section 8 housing voucher program, which bars criminals from living in homes rented with the voucher. Gonter says he and two other members of the Patterson Park Neighborhood Association would get lists of recent arrestees and match the addresses, then notify Baltimore Housing.

Karle's several companies soon became known to them, the couple says over lunch. "They [drug dealers] would get arrested together but be living at different houses," Summer Gonter says. "So how do they know each other? The only connection you see is they have the same landlord."

Once you're attuned to finding connections and using the public records, it's easy to start drawing conclusions. It's easy even to fall into a sort of conspiracy mindset, wherein the rich landlord is allied with felonious tenants and the corrupt housing authority, all corners of the profitable enterprise ready to defend it.

Then again, in Baltimore, where everyone is everyone's cousin, gangs control the jail, and people with criminal records work the docks and in City Hall, it's not possible to just dismiss fears out of hand. Karle is known in City Hall.

"He accuses people of racism," says Councilman James Kraft (D-1st District), adding that community complaints led to a meeting, and Karle "didn't follow through" with promised improvements.

"He's probably being targeted for being a racist and going after people," Karle says of Gonter in a phone interview. "I got nothing to do with the guy. He's a loose screw. He's a racist. He targets poor black families. He sends emails to Section 8-goes around looking for code violations and harasses Baltimore Housing."

Karle's Summerfield Investment Group owns three houses on Gonter's block. Gonter-and Karle's father, Tom Sr.-says Karle owns hundreds of properties, mostly in East Baltimore. "He exaggerates," Karle says of his father, who called City Paper last spring about an old cannon allegedly left in the bottom of an Essex marina ("Loose Cannon," Feature, June 6, 2012). Still, Karle has some assets: Land records show that Summerfield Investment has more than 800 transactions since 2000 covering at least several dozen properties. Karle and his wife live on 2.5 acres in Fallston. He was ticketed in 2011 for failing to attach a front license plate to a 2002 Ferrari.

"I think he targets me because I come from a mixed-race family," Karle says of Gonter.

Karle says Gonter repeatedly emailed snapshots of a house to city officials claiming the grass in front was over 6 inches high. He says Gonter "almost came to blows" with a new neighbor over the license plate on the newcomer's car-which was still registered in Pennsylvania a month after his arrival.

Karle says it all started when a kid on the street threw a snowball at him. He says Gonter called him after 10 p.m. and demanded to know why he was renting to "niggers." (Gonter denies using that language and that he's a racist).