He was arrested on Thursday night by officers from the Directorate of Criminal Investigation and taken to Nairobi for questioning.
Ngengi will be questioned on how he happened to be at the scene of the two high profile accidents.
Apart from being at the scene of Gakuru crash, he was among the first people who were at the scene of the Lake Nakuru helicopter crash.
During the Lake Nakuru incident where pilot Apollo Malowa and others died, Ngengi introduced himself as a "State Pilot".
In a video aired by a local TV station, he said the late pilot was "a friend of ours, who we loved, and that's why I'm here."
In the Kenol accident, he said he was travelling from Nyeri and was being driven behind governor Gakuru's car when the accident happened.
According to sources within the police, upon interrogation, it emerged he was not a police officer but a con who took advantage of the accident.
Sources said Ngengi was coming from Utawala when he got wind of the Kabati accident and drove there to speak with the media.
Police have also confiscated his car for further investigations.
In the two camera interviews, Ngengi wore bluetooth sunglasses - mostly seen on leaders' security personnel.
Members of the public who made fun of him connected their phones and flash disks to sunglasses for the 'bluetooth effect'.
-The Star|