BANGOR, Maine — A Penobscot County jury must decide which is more credible — the emotional testimony of a 13-year-old girl who claims her mother’s ex-boyfriend sexually assaulted her or the repeated denials of rape the defendant made to investigators.

The state rested Tuesday afternoon in the jury trial of David Churchill, 26, of Fort Fairfield, who was indicted a year ago by the Penobscot County grand jury on charges of gross sexual assault, a Class A crime, and unlawful sexual contact, a Class B crime.

The defense is scheduled to begin presenting its case at 9:30 a.m. Wednesday. Superior Court Justice Kirk Studstrup, who is presiding over the trial, told jurors he could convene an hour later than normal to allow them more time to make their way to the Penobscot Judicial Center in the predicted snowstorm.

The trial got under way Tuesday morning with emotional testimony from the alleged victim.

The girl was the first witness after opening arguments by Penobscot County Deputy District Attorney Michael Roberts and defense attorney Hunter Tzovarras of Hampden.

An eighth-grader at a Bangor middle school, the girl described herself as a student-athlete who gets good grades. She cried as she told jurors that Churchill raped her in her mother’s bed early on the morning of July 29, 2009, then dropped her off at her baby-sitting job.

Churchill, who is free on bail, showed no emotion as the weeping teenager described how he undressed and raped her after her mother left for work. The girl testified that she repeatedly told him to stop.

The girl also told jurors she waited a week before telling anyone about the alleged incident. Under cross-examination, she admitted that she told her best friend about the rape but asked her not to tell anyone. Instead, the friend told the alleged victim’s mother, who called Bangor police.

“I was just scared,” the girl said when asked by Roberts why she did not tell someone immediately about what had happened to her.

Under cross-examination about her reluctance to tell an adult about the alleged rape, the girl told jurors, “I was going to eventually tell my mom anyway.”

During the afternoon session, Bangor police Detective Timothy Cotton told the jury how he and fellow Detective Brent Beaulieu worked with the girl while she communicated with Churchill in a live Internet chat in an attempt to get him to confess.

Cotton said that Churchill at first lied about staying the night at the girl’s apartment on July 28-29, 2009, and about communicating with her over the Internet. Under cross-examination by Hunter, the detective said Churchill consistently denied having sexual intercourse with the girl or touching her in a sexual manner.

In his opening statement, Roberts told the jury that Churchill met the alleged victim and her family at a church in Brewer more than a decade ago. After the defendant returned in the late spring of 2009 from a five-year stint in the Marines, which included a tour in Iraq, Churchill began a relationship with the girl’s mother and spent time at their Bangor apartment.

“Listen to the victim,” the prosecutor urged jurors. “Don’t forget what she said and how she said it. It will be difficult for her to talk about, but her story will be consistent.”

Roberts said that Churchill changed the story he told police at least five times.

Tzovarras told jurors they would hear testimony that his client was sleeping on a friend’s couch when the alleged rape took place. He also said that although Churchill’s DNA was found on the sheets recovered from the mother’s bed, the girl’s DNA was not.

No DNA evidence was introduced Tuesday.

A decision about whether the defendant would take the stand was not expected to be made until midday Wednesday.

The jury is made up of five women and nine men, including two alternates. Jurors are expected to begin deliberations late Wednesday afternoon or Thursday morning.

If convicted, Churchill faces up to 30 years in prison and a fine of up to $50,000 on the gross sexual assault charge and up to 10 years and a fine of up to $20,000 on the second charge.