The asking price for the three-bedroom colonial house on a pretty street in Bethesda was $285,000 -- and the owners were shocked when they learned they had received a purchase offer of $135,000. They didn't bother to respond.

The sellers of a Falls Church bungalow couldn't believe it when the buyers purchasing their home insisted that they install a new roof -- even though the roof was only four years old. No way, they said.

And builders throughout the region have watched in amazement as aggressive would-be purchasers made offers that are a fraction of the asking price and demanded that the seller pay all their closing costs. Increasingly, they are politely asking these buyers to take their trade elsewhere.

The "bottom fishers" are out in force in the Washington area these days, hoping to snare the weak or financially faltering home seller or builder by offering a rock-bottom price and the chance to get out from under a crippling financial obligation.

Views of the practice vary.

"They're trying to steal," said real estate consultant Ken Murphy. "They're thinking maybe they will get lucky and somebody will make a poor business decision."

But cash-rich buyers see themselves as sitting in the driver's seat, many in the industry said.

"He who has the gold makes the rules," said real estate broker David Craw, sales manager for Mount Vernon Realty Inc. in Centreville.

In any case, the avidity with which some buyers are bargain-hunting is being called unprecedented in the Washington area.

"I see people making much lower offers than they would have before," said Chevy Chase real estate broker Thomas B. Lamond. "Sometimes it's almost embarrassing to the seller. This is the first time I've ever even seen such low offers."

And it seldom works, except when very expensive homes are involved, according to about a dozen local real estate brokers and home builders. Such offers usually result in anger, a breakdown in negotiations and a waste of everybody's time, they said.

Nevertheless, some industry observers view the arrival of the sharks as a sign that sales activity is starting to pick up and the market may be leveling off at long last.

"The bottom is there when the bottom fishers come out and start fishing," said Douglas Poretz, who works with NVHomes L.P. "The bottom of the market comes when sellers are not willing to go any lower, and I think that's what's happening."

But even those who are critical of the extremely aggressive bottom fishers say they remember when the shoe was on the other foot, and it was sellers who were eagerly and greedily demanding all the cash they could get out of buyers.

They recall home builders raising their prices by thousands of dollars in a single day, leaving those at the end of the waiting line to be priced out of the market.

They recall sellers attempting to extricate themselves from sales contracts, even when the buyers were paying them the asking price, because they suddenly realized that they could do better.

And the critics recall sellers insisting that buyers be barred from placing such basic contingencies in the sales offer as requirements that home inspections be made, that appropriate financing be arranged or that previous homes be sold.

"{What's happening today} is the mirror image of what sellers were doing two years ago," said McLean real estate broker James Warkentin.

From the point of view of the bottom fishers, the down market for home sellers and builders provides them with a unique opportunity to pick up some bargains. They say that housing costs in the Washington area are so out of proportion to what people earn that their low prices are actually a better reflection of reality.

"A lot of people think now is a good time to make very low offers," said Bethesda real estate broker Ken Vogel, who has tried it about a half-dozen times. Most recently, he made a $425,000 offer on a new Potomac home originally listed for $1.2 million. He was turned down, but the home eventually sold at auction for about $650,000.

"It's just a shot in the dark," he said.

His sister Dianna Vogel, a real estate agent, was the would-be buyer who made the $135,000 offer on the Bethesda house listed for $285,000. She acknowledged that her $135,000 offer was much lower than the asking price, but she said that the three-bedroom, one-bath house, which has been used as a rental, is outmoded and in poor repair.

The $285,000 price is even more unrealistic, she said, noting that it would take a high-income, two-career household to afford such a home, yet it is not large enough to accommodate a nanny or other household help that would be required for such a family.

"I'm not out there trying to pull the rug out from under anybody," she said. "They can say no. It doesn't hurt my feelings."

In this case, however, the low offer so angered the sellers that they refused to make a counteroffer and did not respond at all. That was their mistake, Vogel said, because she had planned to offer them up to $150,000.

According to many local real estate brokers and home builders, extreme bargain-hunting usually backfires on the buyer.

"Some people don't want the sellers to make a dime," said real estate agent Patty Smallwood of Century 21/H.T. Brown in Laurel. "But unless sellers really have to move, they are not going to be blackmailed."

Such strategies often fail in the new home market because the profits have already been wrung out ofthe project and the inventory of unsold homes is declining. In some cases, builders say, they have reduced their prices as much as they can.

"Some people think they are going to steal from us," said Chuck Langpaul of NVHomes. "I can tell you, we're not succumbing to it."

In the market for existing homes, such tactics generally fail because home sellers with low mortgage balances, those who could cut their prices substantially, are seldom that desperate to sell. And most ordinary sellers must pay off their existing mortgages and the real estate commission to come out whole.

"Sellers would rather declare bankruptcy than go to settlement and pay $30,000 out of their pocket," said Don Denton of Dale Denton Real Estate, president of the D.C. Association of Realtors. "They just won't, and can't, do it."

Part of the problem, however, is that real values are so difficult to determine in today's volatile market.

Some sellers have clung to their high sales prices despite the change in the market, which has left some homes priced significantly more than the going rates. And with bargain hunters on the prowl, some sellers insist on adding $10,000 or $20,000 to their asking price to leave them more negotiating room with buyers.

"The market is so confused," said real estate agent Gail Belt of Town & Country Realty. "This is a very difficult time for buyers and sellers. Buyers are being told to get in there and wheel and deal. But they're nice people and they don't like it."

The only answer, she said, is for both buyers and sellers to do their homework. Houses that are priced right, based on other recent sales involving similar homes, generally sell for an amount close to the asking price, she said.