For instance, autists argue about whether Richard Trenton Chase was a spree killer or a serial killer (Wiki has settled on spree killer but true crime sites like crimelibrary often call him a serial killer). On one hand, he had no specific m.o. and was so far gone he'd just walk around trying front house doors, conclude he was invited in if they were unlocked, and then just go in and murder everyone inside, take souvenirs, and walk out again, once even leaving bloody footprints.
He took no effort to conceal his gruesome crime scenes and it's unsurprising he was caught fairly quickly. However, he also went home to add his souvenirs to his collection and didn't just immediately go out and kill again.
Andrew Cunanan, the guy who killed Gianni Versace, also had a similar although not as gruesome method of more or less randomly killing people he encountered. He's often called a spree killer even though his killings took place over a period of months and he actually did some planning and attempted to cover up to some extent, although not very effectively.