In the latest episode of BBC Two's "London Spy", it seems that Danny comes to know that an escort was hired to seduce Alex.
According to the synopsis of the episode, the phone directs Danny to a meeting with a man who says he is an escort hired to seduce Alex. Danny recalls talking to Alex about being "the one" for each other.
He tries "0000001" for the code cylinder to open it and that reveals a USB plug. Afterwards, he and Scottie meet Alex's professor who informs them that the USB contains research on a lie detector system that detects lies from the manner of speech patterns.
When the police enquire Danny regarding his connection with Alex's murder, he responds: "This isn't over." Scottie calls him inside him inside a cab and tells him that there will be a note.
Meanwhile, Danny hurries to the park where he met Scottie earlier and finds Scottie's body hanging from a tree.
In the previous episode, Danny was arrested, and admitted that he had experimented with auto-erotic asphyxiation. The police played him a tape of a telephone call, in which Danny told Alex about his sexual history, but Danny knew it was a recording of a conversation that took place in his flat.
The police showed him the logo of a rent boy agency which they said Alastair used, and suggested that he confess to them that, while high on drugs, he accidentally asphyxiated him.
Danny recognised the logo to be from the American's business card before he ripped it up. The police told him if they discover his DNA on the attic sheets he would be charged.
Danny realised they would set him up as the sheets were stolen from his apartment. Danny visited a record producer called Rich, asking if he could give him information about the rent boy agency. Rich offered him drugs, and said he would help him in return for sex, but Danny refused, and so Rich told him to leave.