The jury has retired in the trial of a former-US Air Force pilot accused of kidnapping a nine-year-old girl and sexually assaulting her.

Robert Prussak, 57, approached the girl in London after she became separated from her family during a trip from France on April 22 this year, Isleworth Crown Court heard.

The girl, who cannot be named because of her age, was standing outside Harrods department store in Knightsbridge, central London.

It is alleged that Prussak then walked her to his flat, gave her bitter-tasting water containing the antihistamine Benadryl, and that she felt tired after drinking it.

Prussak, of no fixed address, then allegedly took her to Hyde Park, where he sexually assaulted her. He denies all the charges against him.

During her closing statement on Monday, prosecutor Nneka Akudolu KC said: “‘I cannot believe it’, that was the response from (the girl’s mother), when she was asked how she felt when she was presented with still images of her trusting nine-year-old daughter being walked away from her last known location by an unknown man.”

View of Isleworth Crown Court
The trial is being held at Isleworth Crown Court (PA)

She added: “(The alleged victim) is a very intelligent young girl, when she became separated from her parents she did exactly what she was supposed to do – stop, stop and stay there,” for a family member to find her.

“She was approached by the man who she thought was a good Samaritan, someone who at that point showed an interest in her being lost, and interested in assisting her.”

The court heard Prussak communicated with the girl, who did not speak English, using Google Translate, and Ms Akudolu said: “After communicating with each other using that app, and waiting and waiting for around seven minutes, this individual, we say, switched from good Samaritan to opportunistic predator.

“Because the moment he decided to walk away from the area where she had last seen her family was the moment he decided that he had a different plan for her.”

CCTV footage played during the trial shows the moment Prussak encountered the girl outside Harrods. He can be seen walking past her before stopping to speak to her.

They communicate for a while using his phone and then walk away together.

Video also showed Prussak and the girl entering Chelsea Cloisters, where he was staying, and heading into his apartment.

They spent almost two hours inside before leaving and walking through central London again, footage showed.

Jurors were told that Prussak took the girl to Hyde Park via the Royal Albert Hall entrance, which is popular with tourists, and that they walked past the pond.

In her closing statement, Catherine Donnelly, defending, questioned why Prussak would take the girl “into one of the busiest parks, in one of the most busy parts of the park” to sexually assault her.

She also asked why he would wait until that point, when the effects of the Benadryl he allegedly drugged her with, could be “wearing off”.

She added: “The flat was the place to do it, no-one would have spotted him, (but) whilst there he turned on the television, gave her a glass of water and then did nothing.”

Prussak has an undergraduate and a master’s degree in mathematics and joined the US Air Force as a mathematician.

He became a pilot in the Air Force and now works as a “pilot for hire”, which is what brought him to London on April 10, said Judge Edward Connell, summarising Prussak’s evidence.

Prussak denies three counts of sexual assault of a child under the age of 13.

He also denies one count of kidnapping, one count of committing an offence of kidnapping with an intent to commit a sexual offence, and one count of administering a substance with intent.