The two Scotland Yard detectives have been deployed from the beginning of the investigation, Sky News broadcaster reported, citing former detective chief inspector Mick Neville.
The detectives' talent is reportedly to focus on the less obvious parts of human faces, the parts that are not easy to change, unlike glasses or facial hair.
READ MORE: Ex-Russian Officer Sergei Skripal May Be Dead, His Niece Says
Skripal and his daughter were found unconscious in the UK city of Salisbury in March after an exposure to what UK authorities claim to be a military grade nerve agent. Both have since been discharged from hospital. London has accused Moscow of orchestrating the attack. Russian officials have strongly refuted the allegations, stressing that they were groundless and pointing out that Moscow's request to assist in the investigation had remained unanswered.