The detonation, in the Värnhem area of central Malmö, occurred at 7:25pm on Friday, causing serious damage to a police car.
Police believe their arrest to be on solid ground, with CCTV footage from the scene of the explosion having been obtained, reports TT.
A police cordon around the area has now been removed, writes the news agency.
Images from surveillance camera have been secured, and IT forensics personnel will analyse the images on Saturday.
“Based on [the surveillance images], we can say that the investigation is in a good position,” Ewa-Gun Westford, spokesperson with Region Syd (South) Police, told TT.
Westford declined to give further details of statements given by the suspect during interrogation, or of the nature of the images obtained by police. The investigation remains at an early stage, she said.
The 22-year-old suspect was apprehended by police a short distance from the scene of the incident shortly after the explosion, Malmö Police have confirmed. He was taken in by police along with a 26-year-old, initially on suspicion of criminal damage (allmänfarlig ödeläggelse). Following the examination of evidence by a police prosecutor, the 22-year was subsequently detained.
The 26-year-old was released and police currently have no reason to suspect the involvement of additional individuals.
“We have one person who was released. He was technically involved and under suspicion in the investigation, but the prognosis is that that will be lifted,” Westford said.
Sweden has seen a series of criminal acts targeting police in recent months. In November, a hand grenade was detonated outside a police station in Uppsala. In October, shots were fired at a policeman’s house in Västerås and the entrance to the police station in Helsingborg was damaged by an explosion.
Nobody was injured during any of those incidents. Nevertheless, Malmö chief of police Stefan Sintéus said they must be taken seriously.
In a written comment to TT, Sinteús described the latest attack in Malmö as a “digusting act”.
Politicians in Sweden have also condemned the incident. Interior Minister Morgan Johansson wrote in a tweet that he expects Malmö Police to “come down hard and increase pressure on criminals”.