A 29-year-old man has been arrested on suspicion of murdering a woman and child and stabbing an off-duty police officer who tried to apprehend him in a “tragic, extraordinary and worrying” case, police said. Daniel Boulton was sought by police after his ex-partner, 26-year-old Bethany Vincent, and her nine-year-old son, Darren Henson, were found dead at a property in Louth, Lincolnshire, on Monday evening, with multiple stab wounds. On Tuesday morning an off-duty police officer, who has not been identified, was stabbed by Boulton in Hubbard’s Hills after identifying the suspect and trying to apprehend him. The officer was treated in hospital for injuries not thought to be life-threatening. Boulton was later detained at a farm in Hallington at about midday and was taken into police custody for questioning. Lincolnshire police deployed helicopters, drones, dog officers and firearms officers, as well as bringing in officers from across the east Midlands to secure the arrest. “He didn’t come willingly. We did have to deploy Taser to effect the arrest, and we did find the suspect in possession of knives,” said Lincolnshire police’s head of crime, DCS Andy Cox. “It was a very challenging and risky operation. “This has been a tragic, extraordinary and worrying set of circumstances in equal measure. A woman and child have lost their lives in the most devastating way and I know that their loved ones will be feeling the magnitude of that today and our thoughts go out to them.” He added the force was “really proud of the commitment and bravery” of the off-duty officer who tried to secure Boulton’s arrest, as well as all the officers involved in the “complex and challenging investigation”. “We’re not looking for anybody else as part of this investigation and I want the public to feel safe and secure. This was a very, very unique and rare incident in Lincolnshire,” he said. Cox said officers were called to a property on High Holme Road at 8.29pm on Monday by the ambulance service and found an “absolutely devastating scene”. A one-year-old child was found uninjured at the address and has been safeguarded. “We were really conscious of the risk that was potentially out there that for the wider public,” Cox said. “Now we really hope to deliver justice for Bethany and Darren, and their family and friends as well.” Lincolnshire police are asking anyone who can help with the investigation to call 101, quoting incident 445 of 31 May.