Whitney Houston's funeral

(CNN) -- Close friends and family will mourn Whitney Houston at a private funeral, led by a pastor who has known her for decades, at a church where she honed her vocal skills as a child.

Gospel singer Marvin Winans will give the eulogy at the funeral Saturday at the request of Houston's mother, according to a leader of the church where it will be held.

Winans officiated Houston's 1992 marriage to R&B singer Bobby Brown, said Pastor Joe Carter of New Hope Baptist Church. The two divorced in 2007.

He is also a brother to noted gospel singer CeCe Winans Houston, 48, died Saturday after a member of her staff found her unconscious in the bathtub of her Beverly Hilton hotel as preparations were under way for the Grammy Awards. Emergency crews were unable to revive her.

A cause of death has not yet been determined pending toxicology results that could take weeks.

"When I've seen her, she's ... so full of life. That's why this is so weird. You can't imagine her not being alive," award-winning songwriter Diane Warren told CNN's Piers Morgan on Tuesday night.

There are no plans for a public memorial, but the church in her Newark hometown hopes to set up a large screen outside so residents and fans can watch the proceedings.

"She was able to leave us with so many wonderful memories of that God-given gift," Carter said. "That's what we are celebrating on Saturday."

Carter said he'll officiate the invitation-only service that starts at noon at his church.

The church seats a maximum of 1,500 people, and the pastor said he expects "all these empty pews to be filled with people whose hearts are broken."

In honor of the family's wishes, there will be no public memorial in Newark, city spokeswoman Anne Torres said. The state's Gov. Chris Christie said he plans to issue an order for flags to fly at half-staff at government buildings on the day of the funeral.

Speculation has grown over the cause of death, but a Los Angeles County coroner official has downplayed suspicions that drugs played a major role.

Medication recovered by investigators in her room was less than what is usually present in deaths attributed to overdoses, said Ed Winter, an assistant chief coroner.

"I know there are reports that she maybe was drowned or did she overdose, but we won't make a final determination until all the tests are in," he said.

Winter ruled out foul play and said there were no injuries to Houston's body.

The pop superstar's body arrived at the Whigham Funeral Home in New Jersey on Monday from California on a private plane.

Cissy Houston, the late singer's mother, was waiting at the funeral home, police said.

"Her heart is broken: Nobody expects to bury her child," Carter said. "But she is managing it with miraculous strength. She is so grateful for prayers and thoughts, and that's holding her together."

The coroner's office said toxicology tests could take six to eight weeks, though Beverly Hills police Lt. Mark Rosen said that the coroner's report is expected to be finished sooner -- in two to three weeks.