"I HEARD A POW. It startled me," a witness testified in court yesterday at a preliminary hearing for Police Officer Chuck Cassidy's accused killer. "I saw something blue falling up [against] the window of the Dunkin' Donuts."

Upon hearing witness Cynthia Beckwith's testimony, the wife of the slain officer, Judy, wept.

Judy Cassidy had stayed strong up to this point as she sat in the front row of the courtroom. But tears flowed when she heard how her husband - the man in blue - crashed against the store's outside front window after he was shot at the doorway of the West Oak Lane Dunkin' Donuts Oct. 31.

Cassidy, 54, a 35th District officer, died the next day.

Throngs of police detectives, officers and brass, including new Commissioner Charles H. Ramsey, came to court to show their support for Cassidy's family. His three children, Katie, Colby and John, sat with their mother in the front row during most of the hearing.

The defendant, John "Jordan" Lewis, walked into the courtroom yesterday with a shiny, bald head - recently shaved. Chunky cheeked and rotund, he appeared downtrodden and nervous.

The 21-year-old, who has lived with family members in Hunting Park and Feltonville, faces one count of murder, one count of simple assault, multiple counts of robbery and weapons offenses.

At the hearing before Municipal Court Senior Judge Francis P. Cosgrove, assistant district attorneys Ed Cameron and Jennifer Selber questioned 10 witnesses - incuding employees - from three Dunkin' Donuts and two pizza shops that Lewis is alleged to have robbed in September and October. The proceeding briefly touched upon Cassidy's murder.

Witnesses today, the second and last day of the hearing, will focus on Cassidy's slaying. Hakim Glover, Lewis' cousin, who helped Lewis flee to Miami, "in all likelihood" will testify, Cameron told reporters yesterday.

Beckwith, who worked at the Dunkin' Donuts on Broad Street near 66th Avenue, testified that Lewis robbed the shop, where Cassidy was slain, six weeks earlier. In chilling testimony, she spoke of how Cassidy had been the first officer to respond to the Sept. 18 robbery, and how he had helped her pursue Lewis that day.

It was 11 a.m. Sept. 18 when Beckwith finished her shift. She got into her parked car, then soon received a phone call from her sister, Gloria Beckwith, who also worked in the Dunkin' Donuts.

"My sister [who was in the shop] was frantic on the phone," Cynthia Beckwith testified.

Responding to the phone call, Beckwith, in her car, followed a man on foot - whom she later identified as Lewis - after he left the shop. She called 911. She said she saw Lewis ditch a sweatshirt he was wearing.

When Cassidy arrived, he and Beckwith, driving in separate cars, searched for the robber. But they lost him around 16th and Cutler streets.

On Oct. 31, Beckwith was in the Dunkin' Donuts bathroom when Lewis allegedly again entered. After she heard a gunshot and saw Cassidy fall against the window, she "grabbed paper towels and tried to apply pressure to [Cassidy's head] wound and tried to help him," prosecutor Selber said after the hearing.

Lewis also allegedly robbed the Dunkin' Donuts on Torresdale Avenue near Kensington on Sept. 21; the Dunkin' Donuts on Frankford Avenue near Shelmire on Oct. 13; Oasis Pizza on North 5th Street near Annsbury on Oct. 20; and Feltonville Pizza on Rising Sun Avenue near Front Street on Oct. 25.

Lewis was a frequent customer at Oasis Pizza, testified countergirl Yahaira Melendez.

For Melendez's testimony, prosecutors asked that the courtroom be cleared of two women, both in Muslim garb.

Prosecutors said afterward that Melendez had been approached in Oasis by a woman in Muslim garb who asked about the robbery. Melendez was concerned that the same woman was in court and didn't feel comfortable.

One of the women in Muslim garb, Habibah Aziz, 41, Lewis' cousin, said during a break that she had not intimidated any witnesses and didn't know Melendez. Prosecutors also said Aziz - whom they did not know by name - allegedly had made some kind of "facial expression" to Cynthia Beckwith earlier in the day.

Yesterday's hearing also offered a testy exchange between defense attorney Michael Coard and witness Shaina Lewis, who worked at the Dunkin' Donuts on Frankford Avenue.

Coard nitpicked at her police statement, questioning whether she had mentioned that the alleged robber had a gun. He did not see "gun" in her answers.

At that, Shaina Lewis held up a hard-copy photo of an image from her store's surveillance video and feistily replied: "Did you look at this picture? He has a gun!"

When Coard persisted, she tartly yelled that the police question in the statement asked if the suspect had the store "at gunpoint," to which she replied "yes." Thus, she did not have to say the word, "gun," in her answer.

Witnesses also described an apparent escalation by Lewis toward violence. In earlier robberies, they testified that Lewis had waved a gun while demanding money and yelling something like, "Give me the f---ing money!"

In the Feltonville Pizza robbery Oct. 25 - the one just prior to Cassidy's shooting - witnesses testified to an actual firing of the gun and a physical assault.

Edgar Ceciliano Falla, testifying through a Spanish interpreter, said he had tried hiding in the rear of the pizza shop, where he worked, after a gunman came in.

But the gunman saw him and he "pulls on me and hits me in the head," he testified. He did not know what the gunman hit him with. Ceciliano Falla also could not identify Lewis as the gunman.

He and two other witnesses, who did identify Lewis in court as the armed robber, testified that the robber had fired his gun at the floor of the shop before he left. The robber seemed "frustrated" that he couldn't get more money, Ceciliano Falla testified.

Among the police officers who came to support Cassidy's family was retired Officer John Marynowitz, formerly of the 35th District. Marynowitz remains paralyzed in a wheelchair after being shot in the head 1993 by a drug dealer, who also fatally shot Marynowitz's partner, Officer Robert Hayes, that day.

"I had to show my support to Chuck and his family," he said outside the Criminal Justice Center. "We're the brothers in blue." *