Police have arrested a 29-year-old man on suspicion of murdering a woman and child and injuring a police officer.
Daniel Boulton was detained by Lincolnshire Police at around midday on Tuesday after a 26-year-old woman and a nine-year-old boy were stabbed to death in High Holme Road, Louth, at around 8.29pm on Monday.
The force said both victims had suffered multiple stab wounds, and a knife believed to have been used to inflict the injuries was recovered.
Another child was found unharmed at the property and is being looked after, police said.
An off-duty Lincolnshire Police officer was also injured in the Hubbard’s Hill area of Louth on Tuesday morning amid a manhunt for Boulton.
The force said he was being held in custody for questioning.
A neighbour near the scene of where a man was apprehended by police in Louth said the person detained had attempted to get into another neighbour’s car.
The witness, who asked not to be named, said: “He was hammering on the window of the car saying ‘let me in, let me in’.
“(The other neighbour) is so shook up, she fortunately had the central locking on and managed to drive off before calling police.
“Police found him in one of the farm buildings but they are still looking for something.”
Armed officers and several police vehicles were involved in the arrest at a farm in Hallington, near Louth.
Two officers in high-vis jackets escorted a man into a police van around the back of a farm building.
He was wearing no shoes or socks, ripped tracksuit bottoms, an Adidas T-shirt and a Nike jacket.
Officers have begun conducting door-to-door inquiries around the area and are searching fields behind the farm buildings.
Forensic officers could also be seen entering the property in High Holme Road on Tuesday, where floral tributes were left outside.
Shane Marshall, 18, and his partner Niamh Ismay, 17, who live two doors down from where the double stabbing happened, told the PA news agency they heard a baby screaming at around 8pm on Monday.
Mr Marshall said: “We saw armed police and canine units arrive. We didn’t see any action, we just heard a baby screaming.
“Police said they couldn’t tell us much but they said ‘as you can see, it’s very, very serious’.”
An air ambulance and a number of police vehicles could be seen in the Hubbard’s Hill area where a police officer was injured.
Lincolnshire Police’s head of crime, Detective Chief Superintendent Andy Cox, said: “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.
“We have also seen communities in Louth, and indeed further afield, who will undoubtedly have been anxious about the possible danger in the town since last night. To all of you I want to say thank you.
“You have been listening to our safety advice and sharing our appeals, all of which has helped us to do our job to the best of our ability.
“I also want to thank our officers and other emergency services colleagues. The first responders last night were met with an unimaginable scene and reacted with professionalism to ensure we do what’s right by the victims, and that’s not a situation you can ever really prepare fully for.
“Our off-duty officer today showed how you’re never really off shift and how our staff will always do their very best to protect the public.
“A thank you doesn’t really cover it, and we wish him a speedy recovery.
“Finally, to all the officers and staff who have been involved in this challenging job overnight and into today, thank you for your ongoing commitment and professionalism.
“There is still a lot to do and now the work starts to understand exactly what has happened here and how.”