After a dramatic shootout, Catalan police arrested a former security guard who earlier on Tuesday shot four people in and around the city of Tarragona.

The man's former employer, two ex-colleagues, and a police officer are all receiving hospital treatment with serious injuries, with one of them in critical condition.

The incident began at around 11 a.m. local time, when the shooter opened fire on his former colleagues while they were at work. He had recently been fired from the security company Securitas, according to local media reports.

Before the attack, he sent his former co-workers a threatening email that included a picture of him holding two large guns with knives and bullets strewn out on a desk before him, reported local daily La Vanguardia.

He attempted to flee the city after mowing down his victims, but police were quickly notified and on his tail.

During his escape, he shot a police officer who tried to pull him over on the highway.

He eventually made his way to an abandoned house in the countryside, which police quickly surrounded.

Authorities tried to negotiate with the man, but the situation deteriorated into a shootout, according to police, before they could shoot him in the leg to neutralize and arrest him.

Little more is known on the shooter's motivations, except that it appears to be work-related vengeance./aa