SAN DIEGO (AP) — A gunman in downtown San Diego shot and killed one person and then walked another block and opened fire again, wounding four people before bystanders and later police took him down, police said Friday.

Travis Sarreshteh, 32, was arrested after the Thursday night shooting and was taken to a hospital for injuries after being tackled by two bystanders before police used a Taser to subdue him, said police Chief David Nisleit. The suspect fired a self-made, unregistered ‘ghost gun.’

The attack was “an unprovoked and isolated incident,” Nisleit said.

The suspect is a San Diego resident with a criminal record and was not speaking to investigators, Nisleit said, declining to elaborate. He was being held on suspicion of murder and four counts of attempted murder.

The gunfire erupted around 10:30 p.m. in the busy Gaslamp Quarter, a downtown nightlife district. Nisleit said there would be an increased police presence in the area in coming weeks.

Police found a man fatally shot in a valet area outside a hotel when they received calls that more people had been shot about a block away, police spokeswoman Lt. Andra Brown said. The gunman got into a confrontation with a group of men and opened fire, wounding four others.

Police said the slain man was 28 years old but did not release the names of him or the others. Police said the gunman had walked up to him as he stood outside the hotel and gotten into an argument with him before opening fire and walking away.

A block away, he confronted a group of men and then opened fire on them. He was followed by a group of people who tried to detain him before police arrived and got in a struggle with him, Brown said.

Three victims were being treated at a hospital. A 27-year-old man was shot in his upper body, a 68-year-old man was shot in the torso and a 26-year-old man was shot in his arm. The fourth victim, a 28-year-old man, was treated at the scene for a gunshot injury to his arm.

The four were friends visiting from out of town, Nisleit said. An off-duty medic saved one victim’s life.

The investigation spanned several city blocks, which remained shut down Friday morning.