List of characters who know Subaru Okiya's identity

there are actually up until now 7 people who knows that Subaru Okiya is actually Shuichi Akai in disguise.

Canon

Conan Edogawa/Shinichi Kudo

Conan knew who Subaru was before they even first met, and also trusted him and lent him his house's keys despite Haibara's protest.

Hiroshi Agasa

Agasa is the one who made the Voice-Changing Choker for Shuichi.

Yukiko Kudo

Yukiko is the one who taught Shuichi how to disguise himself as Subaru.

Yusaku Kudo

Yusaku seemed to be informed by his son about Subaru's identity. He even assumed the Subaru persona for one night to lead suspicious away from Akai.

James Black

James was the only member of the FBI aware of Akai's fake death plan as he noticed that Shuichi's fingers were coated by glue. It seemed he secretly kept contact with Shuichi disguised as Subaru.

Jodie Starling

Jodie was able to figure out the plan that Akai used to fake his death, and she managed to figure out Subaru's identity after been told by Camel that one of Akai's catchphrases is " The division of fault is 50/50", the same line Subaru used with Jodie during the Beika Department Store Case after he knocked her down preventing her from chasing after Scar Akai.

Andre Camel

Camel witnessed Shuichi's disguise technique as Subaru Okiya as well as the Voice-Changing choker to modifiate his voice.

Suspicious

there is 3 people who became suspicious about Subaru's identity

Rei Furuya

During the scarlet showdown,Rei was able to discover the trick that Akai used to fake his death as well as Subaru's real identity and the voice-changing choket used to change a voice.But, Conan was able to deceive Rei creating a scenario where both Shuichi and Subaru who was Yusaku in disguise existed as different persons, which made Rei lose his suspicions. However, in Volume 90 Rei's suspicions had been aroused once again as he noticed Subaru is left handed and remembered Yusaku disguised as Subaru is right handed as he removed his cold mask with his right hand. At the end of the case , Rei seemed to be more suspicious about Subaru's identity as he told the latter that he can't wait to pull out his high collar, but told him he won't do it until he obtains real proof.

Ai Haibara/Shiho Miyano

At first, Haibara suspected Subaru to be a member of the Black Organisation as she was able to sense the organisation's smell from him. However, she changed her attitude towards Subaru after the latter reassured her during Detectives' Nocturne when Conan was kidnapped telling her "Don't make that kind of face, i will not let them run away", which caused her to remember something similiar to what Akai told her about her sister; " Don't make that kind of face , i will protect her at cost of my life". At that moment , Haibara begins to suspect that Subaru is Akai, she also have noticed that Subaru always wears high Collars despite sometimes the weather is hot. She even attempted to pull out his collar, suspecting that Subaru is hiding something on it.

Masumi Sera

Sera met Subaru during Yusaku Kudo's Cold Case and found him very suspicious. She have noticed somehow that Subaru is left handed as he was brushing his teeth with his left hand, which may have caused to remember her brother since Akai is left handed as well, however, her degree of suspicions is still unknown.