With several 3d District policemen looking on, Katherine Johnson, 28, the mother of two children, broke a bottle of malt liquor on an outside wall of the Columbia Heights apartment building she has been asked to vacate. That signal led the takeover of the property yesterday by five of her neighbors in a dramatic protest against what they call real estate speculation.

Two women and three men moved mattresses, a table, a chair and themselves into the five-unit apartment building at 2542 13th St. NW without the permission of the owners.

Their takeover was organized by the Columbia Heights Community Ownership Project, a self-described neighborhood land trust dedicated to the halting of real estate speculation. The organization, which believes in collective ownership of property, already has purchased three buildings in the community, through donations according to its president, Harold Moss, who was one of yesterday's squatters.

Yesterday's peaceful takeover was one of the most extreme of various actions taken recently by tenants in the District of Columbia. All over the city, tenants are organizing to stave off evictions and condominium conversions, and in many cases are trying to raise money to buy their buildings themselves.

Moss, who quit his job this summer as chemist for the National Institutes of Health to devote full time to the Columbia Heights organization, says he believes yesterday's takeover is legal. "It's illegal to push people out and not give them alternatives," Moss said. "It should be illegal for profit to be more important than people. Is it that people can't live in them?"

The owners of 2542 13th St. NW don't take the same position. Edward Sean O'Neill, a lawyer who lives on Reservoir Road NW, and David B. Morgan, who renovates buildings and lives on 17th St. NW, bought the building last March for $50,000. O'Neill said that real estate brokers have told them it now is worth between $80,000 and $90,000.

"We bought it as an investment," O'Neill said, adding that they found the cost of operating it as an apartment building was more than the rents produced. Consequently, they sent notices to vacate to the tenants last month.

The Columbia Heights Community Ownership Project then stepped in, and offered on Aug. 28 to buy the building from O'Neill and Morgan for $50,000 with a $10,000 down payment.

O'Neill and Morgan declined the offer and said in a letter dated Sept. 11 that their present plans are not to sell the building. The letter also noted that they have no intention of allowing the organization to take over the property as they had threatened, and would hold the group responsible for any damage to the three-story brick building.

O'Neill and Morgan visited the property yesterday afternoon while the takeover was going on, observing from across the street. They told reporters they have no specific plans for the building and have not decided what they want to do about the people moving in. Morgan said later that they might wait a week before doing anything.

Sgt. Robert Noyes of the 3rd police District said the owners conferred with police yesterday morning about possible action against the squatters. Noyes said that if anyone is arrested, they probably will be charged with unlawful entry. Noyes said he also had talked to the leaders of the Columbia Heights group. They said they are "willing to be arrested," Noyes added.

Morgan and O'Neill said they offered moving assistance to tenants of the building. Some rejected their offer, but two tenants were relocated to other housing in the community, they said. They also said that the tenants are in violation of city housing codes because two apartments are over-crowded.

D.C. City Councilman David Clarke (D-Ward 1) told a rally that accompanied yesterday's takeover he would work to see that legislation taxing the profits of speculators would apply to the building. Clarke left the rally early, however, and called a reporter later to say that he had been invited but did not realize it was an event leading up to a takeover of the property. Clarke said his presence "didn't necessarily mean that I ascribe to the takeover."