Two elderly people tied up in 'appalling' Lincolnshire burglaries
Two elderly people were tied up during burglaries described as aggravated "appalling crimes" by Lincolnshire Police.
A man forced his way into the two properties in Gainsborough on Sunday.
The first raid took place about 20:30 GMT when an 88-year-old woman had her mobile phone and £80 in cash taken.
Three hours later a 75-year-old man was forced to reveal his bank card number after being threatened with a knife during an attack in Portland Terrace.
Detectives said in both incidents the attacker was "a white man, of a slim / skinny build and in his 20's".
Det Ch Insp Pete Grayson said the attacks had left the two victims "very shaken" and that he was surprised at the level of aggression used.
"We strongly believe that these incidents are linked and we are treating this extremely seriously," he said.
"Whoever has committed these appalling crimes is someone that we need to detain and quickly.
"We will have an increased police presence in Gainsborough and will be knocking on peoples' doors appealing for information. A team of detectives will be working on the investigation following up various lines of enquiry and reviewing CCTV."