Memory cards often hold troves of information. Well-meaning people have used the photos and videos stored on them to return lost cards found to their rightful owners.

But a memory card that someone recently picked up off the ground in Anchorage led to the arrest of a city resident this week on a first-degree murder charge.

The card, which the police say a woman discovered in the Fairview neighbourhood and turned over to them on Sept. 30, contained videos and pictures of a man beating and strangling a woman in a midtown hotel room, the authorities said.

Two days later, on Oct. 2, a caller informed the police that human remains had been found outside the city, on Seward Highway near Rainbow Valley Road — about 18 miles from the hotel that was the setting in the videos and pictures found.

“We had two investigations going on,” said MJ Thim, a spokesman for the Police Department.

The police believe that the woman seen in the photos and videos on the memory card is the same woman whose remains were found Oct. 2. She has not been identified.

As police detectives reviewed images on the memory card, they recognized the man seen in them from a previous investigation, Thim said. The police would not comment on the prior investigation.

The police checked with the hotel, TownePlace Suites by Marriott Anchorage Midtown, and learned that the man had been registered to a room there from Sept. 2 to Sept. 4. The carpet seen in the hotel room where the murder took place matches the hotel that the police visited.

On Tuesday, the authorities arrested the man, Brian Steven Smith, 48, of Anchorage, as he arrived at the Ted Stevens International Airport. During a brief court appearance Wednesday, a judge said that he would appoint a lawyer to represent Smith, who said that he could not afford one, according to The Associated Press. Smith is being held in jail with bail set at $500,000.

The woman seen on the memory card had dark hair, according to a charging document, like the remains of the woman found along the highway.

The memory card, according to the police, contained 39 images and 12 videos, all of graphic nature, which begin at 12:59 a.m. on Sept. 4

In the images and videos, a woman is seen being strangled by a man who “had some sort of an English sounding accent when he spoke,” according to the charging document. In one video, the woman is seen fighting back against her attacker, “attempting to scratch at the man’s wrist with her right hand to get him to stop,” as he pressed into her neck with his right hand.

In another video, according to the document, the man said that his hand was “getting tired” before stomping on the woman’s neck with his right foot, cursing and saying that she needed to die. In other videos, the woman is seen struggling to breathe as he “strangled her more and laughed about it.” One video shows the man, at one point, using a wire or cord on the woman.

One image taken Sept. 4 shows the woman on a rolling hotel luggage cart near a black pickup truck, the authorities said. In at least seven images, prosecutors said, the woman is seen “lying face down on what appeared to be a black bed of a truck.” The last date for the images on the card was at 1:12 a.m. on Sept. 6.

Smith, who was born in South Africa, owns a 1999 Ford Ranger pickup truck with his wife, according to prosecutors. After the police obtained his cellphone records through a warrant, they found that Smith’s phone pinged to a location on Rainbow Valley Road along the Seward Highway — near where the remains were found Oct. 2 — at around 1:07 a.m. on Sept. 6. His phone would not ping an Anchorage location until 1:24 a.m., the police said.

Loading... Loading... Loading... Loading... Loading... Loading...

Calls to Smith’s home Wednesday night were not immediately returned.

The police credited the caller who reported the memory card as having provided a critical component in the case. “We believe that we have our suspect in custody,” Thim said, “and we are moving forward with determining the rest of the answers to this investigation.”