Robbers who slashed the throats of four persons during the robbery of a Fairfax County apartment Sunday "meant to kill" the four victims, county police said yesterday.

Police criminal investigations chief Capt. John W. Zelaska said one of the four robbers was heard to tell his accomplices, "Make sure you cut the jugular vein."

No suspects have been arrested in the incident, which has frightened neighbors in the apartment building at 9136 Barrick St., where the robbery occurred.

One neighbor, who did not want to be quoted by name, said: "I've been staying inside. Taken my name off the door. Put an extra lock on my door. And I'm thinking about moving out."

Another neighbor said she has a gun for protection, and "if anybody knocks on my door, I've got a gun handy."

The victims - two in serious condition - remained at Fairfax Hospital yesterday where telephone calls and visitors to their rooms were being screened.

Listed in serious condition were Laura Bombere, 18, of 3139 Highland La., Fairfax, and David C. Parish, 20, a former Northern Virginia resident who now lives in Hanover, Pa.

Debra Telford, 20, of 2530 Leeds Rd., Oakton, and Stephen Dowell, 20, who lived in the apartment where the robbery occured, were in good condition.

Neighbors, relatives, acquaintances and police said they were baffled by the incident in which the robbers took watches and rings from the victims before tying them up and slashing their throats.

"It's a strange case," said Capt. Zelaska."If it's a simple robbery, why would anyone want to kill anybody?" he added, "If it was a robbery attempt, there really wasn't much taken," he said.

Zelaska said police were trying to determine if anything besides the jewelry was taken.