For the past several weeks, there has been an exodus of tenants at 1711 Massachusetts Ave. NW, following the unexpected sale last month of the Boston House. Tenants said they were unaware the building was up for sale until it had already been sold to the Synanon Foundation, Inc., a drug rehabilitation program founded in California nearly 20 years ago.

In a letter dated May 1, the building's management, Stuart A. Bernstein & Co., informed Boston House residents that Synanon had purchased the building for use as their Washington headquarters and intended to occupy the 70 apartments on the building's top two floors by September. The building has 270 units.

"In order to avoid giving eviction notices," the letter stated that the foundation was offering financial incentives to tenants willing to vacate their apartments by July.

Under the incentive guidelines, tenants on the seventh and eighth floors would receive $800 if they informed management, by written notice by May 15, of their intent to vacate by June 1. Tenants willing to vacate by July 1 would receive $400 if they informed management in writing by June 1.

In addition, 25 tenants on floors one through six were offered $500 of they presented written notices by May 15 to vacate their apartments by June 1. This arrangement was being made to help Synanon relocate seventh and eighth floor tenants on other floors, the letter said.

The notice further stated that Synanon had informed Bernstein and Co. "that tenant services and building personnel would not change in the forseeable future." However, remaining tenants said they recently received notices that they could not use the builing's parking lot after June 30.

Before moving into the building, members of Synanon met with tenants to explain their purpose for coming to Washington.

According to tenants, they were told that Synanon will open a food and clothing distribution center in Washington and use the top two floors of the former Boston House for offices and residences for their personnel.

Tenants said they were further assured that the building would not be used as a rehabilitation center. They were told that another building has been purchased elsewhere in Washington to be used for the food and clothing distribution program.

Both Synanon and Bernstein office have consistently refused to discuss with a reporter the sale of the building and the foundation's proposed programs.

The sober, grey "Boston House" insignia over the entrance of the building has disappeared. Occasionally, Synanon members, identified by close cropped haircuts, denim overalls and casual shirts that tenants call "their uniform," can be seen sitting in front of the building.

Some apartments on the eighth floor have already been converted into offices. Informal hand drawn name tags reading "Bruce and Rosa" or "Dean and Kathy" adorn the front doors of apartments to identify the new occupants.

On June 2, one day after the first deadline for tenants voluntarily vacating apartments, a huge moving van stood at the entrance of the building waiting to receive the few belongings of a former tenant vacating her efficiency apartment. She said she has not yet received her incentive payment.

As the woman's belongings were loaded on the van, members of Synanon carted boxes of food and househould items into the building. A member of the moving company, B & R Movers, said the company has moved 10 people from the building over the past few weeks.