NAIROBI – Karen Wambui walked slowly through the Nairobi city morgue’s turquoise and yellow iron gates, still trying to process what she had seen inside.

She had just confirmed that the last body still there from the Westgate Mall attack nearly a week earlier was that of her son, Calan Munyaka.

The 27-year-old was one of 37 victims of the al-Shabab terrorist assault whose bodies were brought to the single-story main morgue building in the Kenyan capital, where a crucifix is nailed above the wooden entrance doors and the smell of the dead drifts out the open windows. Other bodies were taken to city hospitals and elsewhere.

For nearly a week, Munyaka lay in the morgue, identified only as “Kenyan male, adult.”

On Friday afternoon, the pathologists pulled Munyaka’s corpse from a refrigerated chamber and showed Wambui.

“I’ve just seen a gunshot,” she said, wiping her eyes with a light blue sweatshirt. “Here,” she added, pointing to the left side of her neck.

Officials say at least 61 civilians and six security troops were killed in the four-day takeover of the mall by the al-Qaida-linked militant group. With the Kenyan Red Cross reporting an additional 59 people still missing, the toll is expected to rise and the morgue may fill up again, though the government maintains it has no reports of anyone unaccounted for.

Kenya’s security services made another arrest Sunday in connection with the attack, a top official said, but declined to say how authorities believe the person was involved in the siege.

Kenya has arrested 12 people since the attack but three have been freed, Interior Minister Joseph Ole Lenku said. He declined to say if any of those arrested had been in the mall during the attack.

Kenyans have become increasingly frustrated over the government’s unwillingness to share information about the attack. Almost no details have been released about what happened after the first hours of the siege. “We ask you to bear with us,” Lenku said of the government’s unwillingness to share information.

While the mall was a chaotic scene for many hours after the attack began, with people moving in and out of the upscale shopping center, Lenku insisted no terrorists could have escaped. “Our forces sealed off every point of exit,” he said. “It was completely secured.”

The Westgate Mall was packed with midday Saturday shoppers on Sept. 21 when the teams of al-Shabab gunmen stormed the building and opened fire. Authorities believe as many as 15 attackers were involved, but only six of their bodies have been identified so far — five who were said to have been killed by security forces’ gunfire and one who died in the rubble of the building’s collapsed roof.

The Nairobi mall was patronized by the Kenyan elite and wealthy foreigners, but Calan Munyaka was neither of those. He sold clothes for a living but didn’t work at the mall, his mother said.

Her last conversation with him was by telephone two weeks earlier, and he was excited, introducing her to his fiancee and announcing she was a month pregnant. He worked out plans with his mother for the three of them to meet in person next month.

Wambui watched the mall attack drama unfold on television from her home in Kisumu, on Lake Victoria. She had no idea her son was at the mall and still has no idea why he was there.

But she knows he was one of the first to die — his body was among the first brought to the city morgue on the first two days of the siege.