There is "no independent evidence" that proves Rolf Harris was at events where he allegedly groped two women, a court has heard.
Jurors at Southwark Crown Court were told that despite searches of newspaper archives, no trace of the entertainer appearing at a community centre near Portsmouth in 1969 or an event in Cambridge in 1975 could be found.
One alleged victim, then aged 14, claims Harris, 84, groped her bottom outside a Celebrity It's a Knock Out event in Cambridge. She said he was acting up for a crowd by barking at a dog before he grabbed her.
Defending, Sonia Woodley QC told senior investigating officer Gary Pankhurst: "There is no independent evidence of any kind to put Mr Harris in Cambridge in the year of 1975."
The detective sergeant said that the alleged victim had not been entirely sure of the date, but "1975 was clearly she felt the most certain".
Another woman claimed Harris touched her intimately when she was seven or eight after she queued to get his autograph at a community centre near Portsmouth in 1969.
Again, despite searches of local newspaper archives, council records and letter drops appealing for witnesses, no confirmation could be found that Harris had been there.
This included looking at copies of the Portsmouth News between January 1967 and May 1974.
When the allegation was put to Harris, he told police: "I would simply never touch a child inappropriately."
The artist is accused of 12 counts of indecent assault on four alleged victims between 1968 and 1986, all of which he denies.
Earlier the jury of six men and six women was shown cine film footage of a third alleged victim who was friends with Harris's daughter Bindi.
It showed a group of men and girls wearing shorts and t-shirts swimming in a fast-flowing river, clinging on to rubber rings.
The footage, taken in Australia in 1978, also showed the alleged victim swimming in a pool, wearing a light-coloured bikini.
Mr Pankhurst, from sex crime inquiry Operation Yewtree, was then taken through parts of the prosecution evidence.
He confirmed that three weeks after the inquiry was launched in October 2012, officers received a referral from the NSPCC.
A counsellor claimed that they had been dealing with someone since 1998 who had alleged they had been abused by Harris as a child.
The next day, October 25 2012, the woman herself came forward, but only agreed later to give officers her name.
The following month Harris's Bray home was searched by police while he was out of the country, but his daughter Bindi was present.
They seized exhibits including the cine film, and Harris agreed voluntarily to speak to police.
In his first interview he gave a prepared statement about Bindi's friend that said: "I categorically deny having had any sexual contact with the complainant whatsoever while she was under the age of 16. I accept that I did have a consensual sexual relationship with the complainant when she was an adult. I finished the relationship and she was extremely upset."
The alleged victim did not make her claims public, and the first time they were made publicly known was at the opening of Harris's trial, the court heard.
Another alleged victim, Tonya Lee, who has waived the normal right to anonymity in sex cases, was interviewed by British police in Australia.
They spoke to her separately from her boyfriend Fian McDaid, because he was "controlling", the court heard.
Mr Pankhurst said: "He was very suspicious of us and appeared to want to manage the whole situation."
Ms Lee gave a magazine and a television interview to Australian media in return for a fee, the court heard, leading Harris to question her motive for coming forward.
He said in a police statement: "The allegations she has made have shocked and distressed me. They are absolutely without foundation and I deny them in the strongest possible terms."
The entertainer went on: "I'm afraid that her actions do suggest that she may be motivated by a desire for fame and financial reward."
Later McDaid, who served a jail term for assaulting Lee, claimed that she had invented her allegations, the court heard.
The two remaining victims came forward before Ms Lee's media interviews were made public, jurors were told.
The court heard that council records showed there was a planned lottery event with "a big-name celebrity" dishing out prizes in Cambridge, on the green where the alleged victim said the assault took place.
However, police had been unable to confirm who the famous figure was.
After reading a series of agreed facts to the jury, Ms Wass confirmed that the prosecution case is now finished.
The jury was sent home until Tuesday, when Harris's defence is set to begin, and is expected to start with the entertainer giving evidence.