A National Bank of Washington teller was shot in the head and killed yesterday morning moments after she complied with the demands of an armed man by putting money into a bag and handing it to him, D.C. police and witnesses said.

The robber, after going to five other tellers and demanding that they put more money into his white plastic garbage bag, then ran out of the National Bank of Washington branch at 301 Seventh Street NW, commandeered a taxicab, and escaped, police and witnesses said. He was last reported getting out of the taxi near Fifth and M streets NW, about 12 blocks from the bank.

After the robber had shot the teller and was leaving the bank, he turned and said, "Thank you very much, ladies and gentlemen. I love you for your cooperation. I love you," a bank employe told a reporter.

The slain teller, Sonya Grillo Durham, 36, of 1863 Newton St. NW., was shot at twice, and one bullet struck her in the middle of the forehead, police said. She was taken to George Washington University Hospital and died about 2 1/2 hours after the 9:30 a.m. incident.

Another bank employe, badly shaken, also was taken to the hospital. She was treated for an anxiety attack and released.

One teller, who asked not to be named for fear of retribution, told a reporter that after Durham handed the bag over the counter, the robber "just picked that bag up and shot her and walked right on down the line . . . as if nothing even happened. It was like he did this every day."

Said another bank employe, who also declined to be identified: "He shot Sonya and she cooperated. She did exactly what he told her."

Police yesterday described the gunman as being a short, stocky man in his mid-20s with a drooping mustache. Police and witnesses said he wore a blue baseball cap with gold embroidery trim, a black waist-length ski jacket and black pointed-toe shoes.

Durham, who leaves a 14-year-old daughter, would have been employed by the bank one year as of next week.

A teller who said she had been a friend of the victim said that Durham "was fantastic. She seemed aggressive but underneath it all she'd call you 'babe' and 'honey' and she'd put her arms around you every so often."

Luis Grillo, a cousin of the victim, told a reporter that Durham left jobs as a teller with two other banks before going to work for National last year. "She really didn't want to go back into banking for many reasons -- including the risk -- such as what happened today," he said.

"She was a strong lady, a good lady" who sacrificed for her daughter's education at a private school, Grillo said.

There was one unarmed bank security guard present during the robbery, but he told a reporter afterward that he was powerless to act. "What could I do?" he said softly. "A man shooting off a gun point-blank like that . . . I didn't have a chance to do anything."

Police said that there were about five customers in the bank when the robber entered. Some of the customers dropped to the floor as he approached Durham, the first teller.

A robbery squad official said that the robber told Durham, "This is a holdup. I want your money. Don't make a move."

Police said that after the shooting the robber ran out of the bank and tripped over a bicycle that was on the sidewalk, then got back up and jumped into the cab, pointing a gun at the driver and directing him where to go.

D.C. police and federal law enforcement officials later converged on a four-block square area around Fifth and M streets NW where the gunman left the cab. Carrying pictures of the suspect taken by a bank camera, they knocked on doors and questioned people in the neighborhood for more than five hours.

After being questioned by two detectives, one man standing with a group of seven others outside a vacant town house later told a reporter: "In this neighborhood, some things you see, some things you don't."

Bank officials said yesterday that a $10,000 scholarship fund would be established for Durham's daughter, and that there would be a reward for information leading to the arrest and conviction of the robber.

Police said yesterday that the incident was the 33rd bank robbery in the District of Columbia this year, compared with 70 at this time a year ago. The last bank robbery involving a death was in December 1980, police said.