Even after her throat was slashed with enough force that a neck vertebra was nicked, a Huntington Station teenager likely did not die right away, the Suffolk chief medical examiner testified Tuesday.

“In my opinion, the death would not have been instantaneous, but it would have been a matter of minutes,” Dr. Michael Caplan testified during the trial of Adam Saalfield, 22, in Riverhead. Saalfield is accused of killing his neighbor, Maggie Rosales, 18, as she was walking to meet some friends the night of Oct. 12, 2014.

Rosales and Saalfield did not know each other, even though they lived on the same street, witnesses have said.

Using autopsy photographs and a video of the killing from a furniture store surveillance camera, Caplan explained to jurors and state Supreme Court Justice John Collins how he believed Rosales died. As his testimony began, Rosales’ father excused himself from the courtroom.

Throughout Caplan’s testimony, Saalfield did not look at the screen where the photos and video played.

During questioning by Assistant District Attorney Raphael Pearl, Caplan described four wounds to Rosales’ neck. Two of them were insignificant — a scratch about 2 1⁄2 inches long on the right side of her neck, likely caused by a blade, and a small nick likely caused by the tip of a blade.

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Between those two wounds, was a gaping slice about 2 1⁄4 inches long. A similar wound was on the front of her neck, Caplan said.

The slice on the front cut open a carotid artery and a jugular vein and cut through her windpipe. The wound on the right cut through the vein and artery and left the nick in her vertebra, Caplan said.

“That would take a substantial amount of force to cause that injury,” he said.

Caplan looked at a knife police seized from Saalfield when he was arrested after the killing on an unrelated drug charge and said it was capable of causing the wounds.

During cross-examination by defense attorney Craig McElwee of Hauppauge, Caplan said he did not look at any other knives in the case and said that many other knives or sharp instruments could have caused such wounds.

In the video of the attack, which lasted less than a minute, the assailant walked up behind Rosales, shoved an object to the right side of her neck, spun her around and took her to the ground. He knelt over her for a short time and pulled her to her feet before they fell to the ground again.

She was found lying face down in the same spot about a half-hour later by a pedestrian.

Caplan said her death likely resulted from a combination of massive blood loss, aspirating blood into her lungs through her cut windpipe and air getting into her jugular vein and obstructing blood flow.