The prosecution said that Mangs had admitted one of the three murders he is charged with to a friend while out on a walk. The defence denied the claim.
"He is interested in seeing how different people react to different things. That's why he has claimed to certain people that he is guilty of crimes," Douglas Norking, one of Peter Mangs' legal aids, told Swedish Radio News.
Mangs also denied that he was never at any of the crime scenes mentioned in the charges against him.
The defence emphasized that there are no finger prints or traces of DNA that tie Mangs to any of the murders or attempted murders.
The prosecutor mentioned that Mangs consulted psychiatric services in 2003 admitting he was "easily insulted" and had an "interest in death".
DVD copies of the films "Natural Born Killers" and "American Psycho", a specially designed safety vest and several pairs of glasses were among the objects the Malmö police found in Mangs' apartment after his arrest.
The police also found a copy of the book "Lasermannen", which examines the actions of a sniper who targeted immigrants in and around Stockholm during the early 1990's.
The majority of the crimes that Mangs is suspected of were committed against foreign-born Swedes, but the police has repeatedly said that there is no "clear motive" which unifies all the alleged attacks.
Mangs' defence denied any xenophobic or racist tendencies on the part of their client.
Security was tight around the much-publicized trial against Peter Mangs, the suspected serial killer charged with three murders and twelve attempted murders. The police has said that there is no "clear motive" unifying all attacks, most of which were carried out against foreign-born Swedes.