Just collecting together the two accounts of the screams & running man so that speculation doesn't become false fact.
1. We do not know where the witness lives - seems quite likely it's Claremont Avenue but we do not know.
2 Unless reported elsewhere, we do not know the age of the witness, so let's not refer to him as a "young lad". His father may be elderly.
Daily Mirror, 7 Feb
A local, who wanted to stay anonymous, said the cries rang out “seven or eight” times and went on for about 15 minutes.
They said they then spotted a man running out of Oak Road Playing Fields – minutes away from Libby’s home in Hull.
…...
One resident said: “I woke at about quarter past 12 and there was a scream. It sounded like a woman’s scream towards the back of the park, where the river bank and pond is. Then 30 seconds later there was another scream. She must have screamed seven or eight times. All of the screams had gaps between them. The screams must have gone on for about 15 minutes.
“They sounded eerie, they sounded dark. Then I saw a male running.”
Girl heard screaming in park just minutes after Libby Squire vanished
Daily Telegraph, 9 Feb
Police have also stepped up the search of an area around the Oak Road playing fields, where a witness described hearing a woman screaming and a man running away late last Thursday night.
Speaking to the Telegraph, the witness's father, whose house overlooks the fields, said:
"My son heard the screaming - he heard about six or seven screams - and he went to look out of the window. He said it sounded like he was moving. It was intermittent."
He went on: "The man he saw wasn't dressed for a night out. He wasn't dressed for the weather.
He saw him running for around 40 yards, sprinting at times. He said he was on his own and he wasn’t looking back."
Libby Squire: Police examining CCTV footage which may show missing student