The body parts are coming in 400 a day now, and the medical examiner's office is bracing for 1 million in all.

Agonized loved ones can hardly bear the wait, but it could take weeks or even a year to identify everyone killed by the twin suicide attacks on the World Trade Center.

On Tuesday, city officials said crews had recovered 218 bodies and identified 152 victims. The remaining corpses — along with hundreds of bone and tissue fragments — are being sampled for DNA so eventually friends and relatives will have something to bury.

James DeBlase, whose son James Jr. is among the 5,422 missing, knows the pain of waiting.

"My wife wants to know how he died," DeBlase said. "Did he suffer? Was he crushed? Did he fall? Me, I just hope he didn't suffer."

Robert Shaler, director of forensic biology for the city medical examiner, said his office must wait for special software from the FBI before beginning the DNA tests on thousands of samples. Pathologists are already collecting fingerprints, X-rays and dental information from the dead.

The DNA software is expected late next week, but it could be longer before matching begins — the city wants to wait until it has a substantial number of DNA samples. Just how many are enough hasn't been decided.

The real delay is — and will continue to be — finding victims. The need to carefully sift the rubble of the Trade Center for possible survivors and clues to the crimes has hobbled the recovery effort.

Shaler expects the daily number arriving at the morgue will double or triple as the focus shifts from rescue to recovery.

Then, the plan is to analyze every recovered body part. That's done by matching the remains against samples taken from personal items belonging to the missing, such as toothbrushes or hairbrushes, that may have traces of DNA left on them. If those items are not available, close relatives are asked to give their own DNA samples. The latter can be matched to unidentified remains using a method similar to a DNA paternity test.

The process could take a year or more, said Mitch Holland, vice president of Bode Technology Group, a genetic analysis laboratory in Springfield, Va. He questioned the city's intention to test every scrap of biological material.

"To get down and test every single piece will do nothing but bog down the entire system," Holland said. "Our recommendation is that you start with anatomically recognizable material, with the goal to identifying everybody who is missing."

After that, smaller pieces might be tested so they could be returned to families along with the larger parts.

The laboratory work will be performed by two companies well-known for their ability to perform large volume DNA analysis — Celera, based in Rockville, Md., and Myriad Genetics, based in Salt Lake City.

Both companies have valuable experience. Celera raced against the federally funded Human Genome Project to sequence the entire human genetic code, while Myriad is best known for developing a genetic test for increased vulnerability to breast cancer.

Carlos Salas, who lost his father, Hernando, in the Sept. 11 terrorist attacks, knows the relief Celera and Myriad's work might bring. Local hospitals were able to identify his father, who was buried Monday.

"At least I have relief. A lot of people don't have that," Salas said. "I feel bad they don't have a body to bury like I did."