Immigration Enforcement/intelligence team

My colleague at work wants some advice. When completing the FLR (M) Partner application form, her partner had lied on one of the questions on the application form- "did you and your partner stay together since the time he entered the UK? Both did not stay together for the full duration of the visa. For the initial 2 years, the applicant was living and working elsewhere. The visa was however granted.

However some distant cousin who has had family issues with them, have reported this as an Immigration Crime on the gov.uk website.

My colleague through a common family friend has got to know about this and is now worried about the consequences.

I have read that the immigration enforcement/intelligence team are the ones responsible for investigating immigration crimes. Do they liaise with the Home Office? What actions can they take and does the police get involved?

My colleague is concerned that the police will come to their house and arrest/detain her husband and might even deport him.

Do they take physical action or through written means of communication like emails/post.

Any advice will be appreciated.

Ab initio there was no reason for your colleague to lie about this as it does happen that due to job requirements one party could be in another town/city for work and get an accommodation there though there is still a main home where the other partner lives and the one working away comes to regularly.
Should checks be needed what was the extent or detail of the applicant, how frequent was coming home?
On the basis of probability this should not pose a problem for a genuine marriage.

Thanks for your reply.
They only communicated via text messages. They did not make any visits to each other during the period.