The Night Clerk (2020) on Netflix

Plot summary

Bart Bromley has Asperger syndrome and lives with his mother. He works the night desk at a hotel, where he hides cameras in a guest room and studies the live feeds to copy how people speak and move. During one shift he watches a guest named Karen, then sees the man she has let into her room argue with her and beat her. Bart drives back to the hotel to help, and his co-worker Jack finds him in Karen's room, where she is dead. Detective Espada questions Bart, whose account of the night does not hold together, and points out that the wallet Bart says he returned for was needed to pay for the ice cream he had already bought. Reassigned to a different hotel, Bart meets a guest named Andrea Rivera.