Adam Singer, aged 30, has been sentenced for the murder of Sally Ann Harrison in Plymouth in April 2012.
He was sentenced to life imprisonment at Plymouth Crown Court, to serve a minimum of 18 years.
Following the sentencing Detective Inspector Nassaris, the senior investigating officer said: "We are pleased with the result today and glad that justice has finally been done for Sally and her family. Sally has been described as; a beautiful young woman and loving mother who will be sadly missed by all her friends and family.
"This was a particularly brutal murder of a young mother in her own home whilst her daughter was also in the house. Our case was that this was a premeditated murder, which had been planned for some time by Singer.
"He constructed an elaborate plan to murder Sally. He created an on-line profile for a fictitious person and suggested that person was following Sally and talked about bottling her. Singer stole a weapon from work, murdered Sally, then left their child at home alone with her dead mother for about six hours whilst he covered his tracks.
"He disposed of the weapon and his blood-stained clothing, neither of which has been found. He then created an alibi by going to his new girlfriend's, sending a text to Sally as though she were still alive and ensuring that on the way home he was seen on CCTV at a filling station.
"When he got home he called the emergency services and pretended he had just found the body of Sally, suggesting someone must have got into the house and murdered Sally whilst he was out.
"Singer never expected to be caught for this crime and thought he could fool everyone in to believing he had nothing to do with the murder. I would like to thank the detectives from the Major Crime Team, the local police who initially responded, the Scenes of Crime Officers and other specialists who worked on this case.
"It was only through their professionalism and perseverance that Singer's story was eventually shown to be a web of deception. This offence occurred at a particularly demanding time, with reductions in resources and increases in workload, but everyone has risen to the challenge and worked long and hard to ensure standards have been maintained or improved.
"Whilst we are satisfied with the result we cannot be happy as our thoughts at this time are with the family and especially with Sally's daughter. Singer claimed he would do anything for his daughter but his only real thought was for himself. His callous and selfish act has resulted in his daughter's mother being murdered and her father being imprisoned for life."