Swansea Crown Court has heard how Lewis Haines (31) murdered 18-year-old Lily Sullivan (pictured) and dumped her body in the Pembroke millpond before telling his girlfriend, “I’ve strangled somebody”.

Haines, a father-of-one from Lamphey, had previously denied the charge but changed his plea to guilty a week before trial. A trial of facts was held this week to determine whether there was a sexual element to the killing, as this raises the life sentence minimum from 15 years to 30.

The court heard how Haines had spotted the teenager in a nightclub in Pembroke but was told “she’s too young for you.” He had been drinking heavily.

After partying with friends, Lily was seen heading away from the nightclub with Haines in December last year. CCTV footage was included in evidence.

Rejecting claims made by Haines that he tried to save Lily from the water, the judge, Paul Thomas QC found that the murder was motivated by sexual “frustration”.

The judge said it was significant that Lily’s phone and jacket were left in an alley: “she did not leave those voluntarily at that spot”; and that her top was found slightly damp on vegetation near the Millpond: “I come to the conclusion she was not wearing that top when she went into the river. Had she been, it would have been completely saturated. I find it was removed from Lily against her will by Lewis Haines.”

Post mortem examination had found that there was no evidence of sexual assault.

“Lewis Haines struck Lily on several occasions, as her injury and the presence of blood show” continued the judge. “That was done with significant force. He then strangled her, probably to death, before putting her into the Mill Pond where she would not be seen at night.”

The judge praised Lily’s family, of whom many were sitting in the gallery, for the dignity they had shown.

Haines is due to be sentenced today (Friday).