Knife Crime
Early Warning Signs

Physical signs alone are not sufficient to determine knife crime involvement but should be documented and factored into a welfare assessment alongside behavioural and social indicators.

On the young person's body

• Unexplained cuts, grazes, or puncture wounds — particularly to the hands, arms, or torso
• Scarring consistent with slash or stab wounds that the young person is unable or unwilling to explain
• Bruising inconsistent with accounted-for activity; healing injuries at different stages
• Reluctance to remove outer clothing in warm weather (concealing wounds or a weapon)
• Noticeable change in gait — walking stiffly or awkwardly with no medical explanation

On or around the young person

• Knife, blade, or improvised weapon found on person or in bag — including craft knives, lock knives, zombie knives, or machetes
• Carrying items consistent with weapon storage: adapted clothing, sheaths, magnetic strips inside waistbands
• Multiple mobile phones (burner phones used to manage drug lines or gang communications)
• Large amounts of unexplained cash or high-value items (trainers, jewellery, clothing) inconsistent with family income
• Coded notebooks, handwritten ledgers, or debt lists in pockets or bags

Attendance and social patterns

• Persistent school non-attendance, unexplained exclusions, or sudden changes in behaviour reported by school staff
• Withdrawal from previously enjoyed activities, sports clubs, or social groups
• Sudden change in friendship group — new, older associates not known to family
• Fear-based compliance — the young person does what others say without question or challenge
• Arriving at school late, leaving early, or being found out of area during school hours

Communication and demeanour

• Refusal to make eye contact with authority figures; hypervigilance in public spaces
• Use of gang-associated hand signals or terminology (see language decoder in Resource 01)
• Angry, hostile, or disproportionate response to questions about friends, location, or activities
• Sudden acquisition of gang-associated clothing: specific colour combinations, bandanas, or postcode-coded items
• Claiming to be going somewhere but CCTV or intelligence places them elsewhere
• Carrying a weapon "for protection" — articulating fear of rival groups, especially around transport hubs or schools

Fear and coercion markers

• Expressing fear about travelling certain routes or entering specific postcodes
• Reluctance to return home at agreed times — may indicate competing control from gang
• Reports of being followed, threatened, or targeted by other young people — may be a victim of county lines debt bondage
• Visible anxiety when a mobile phone rings; acting on the call immediately and leaving without explanation

Drill music and its associated social media ecosystem are operationally significant. Gangs use TikTok, Snapchat, and Instagram Reels not merely to share content but to conduct real-time psychological warfare against rivals — goading violent responses, broadcasting perceived victories, and maintaining hierarchical dominance. Officers should treat a young person's social media footprint as potential intelligence, not background noise.

Indicators a young person is engaged in digital drilling

• Phone is hidden from adults but used constantly — especially late at night
• Young person becomes distressed or aggressive when videos are shown to them
• Online profile uses gang imagery, postcode abbreviations (e.g. "SN1", "LN1", "B21"), or drill artist aliases
• Searches force intelligence systems for gang handles associated with the young person's name
• Wearing specific colours or brands associated with online gang identity

Location intelligence

• Regularly found in areas associated with gang activity — parks, stairwells, transport hubs — outside of school hours
• Reported at addresses not known to carers or social workers, especially in different boroughs or force areas
• Found in groups of three or more, with older individuals present, and unable to account for the relationship
• Associates with known Nominal persons on local intelligence systems — cross-reference on approach

Family and home environment

• Parent or carer has reported the child missing more than once in a rolling 12-month period
• Family has received threats, had windows broken, or reported unknown individuals watching the address
• Sibling or relative already known to be involved in gang activity
• Evidence of weapons or drugs being stored at the family home without the young person's knowledge (line controller using family address)