A crime is considered detected when AGS have identified and sanctioned a suspected offender for the crime. Valid sanctions may include charges and summons, formal and informal cautions, and fixed penalties depending on the offence type. There are some limited circumstances where a detection is permitted even though no suspected offender has been sanctioned. The rules governing crime incident detection are outlined in the Guide to How Crime is Recorded and Counted by An Garda Síochána.

A crime may have more than one suspected offender and they may be sanctioned by different means. Table 6.1 shows the number of persons detected for crimes reported in 2019 and the proportions of suspected offenders who were sanctioned using different sanction types.

For crimes reported in 2019, most suspected offenders were sanctioned by issuing them with a charge or summons, with it being at least two-thirds in each offence group and more than this for a number of them. All suspected offenders for Group 01 (Homicide) were issued charges or summons, while other offence groups had 80% or more of suspected offenders sanctioned in this way, for example 93% in Group 10 (Controlled drug offences), 89% in Group 06 (Robbery, extortion and hijacking offences), 87% of Group 07 (Burglary and related offences) and 80% in Group 02 (Sexual offences). The proportion of suspected offenders who faced prosecution was lower in what may be regarded as less serious offence types where an alternative sanction was more frequently deemed appropriate, such as in Group 08 (Theft and related offences) incidents (76% charge or summons), Group 12 (Damage to property and to the environment) incidents (71% charge or summons), and Group 13 (Public order and other social code offences) incidents (66% charge or summons). See Table 6.1 and Figure 6.1.

Juvenile cautions, which can be used for suitable suspected offenders aged under 18, was the next most common method of sanction (after charge or summons), and was applied to about one in six suspected offenders sanctioned for Group 11 (Weapons and explosives offences) offences and Group 12 (Damage to property and to the environment) offences. See Table 6.1 and Figure 6.1.

Adult cautions were used in just less than one in ten Group 03 (Attempts/threats to murder, assaults, harassments and related offences) offences (9%), Group 08 (Theft and related offences) offences (9%), Group 12 (Damage to property and to the environment) offences (8%), and Group 13 (Public order and other social code offences) offences (9%). See Table 6.1 and Figure 6.1.

Fixed charge notices or fixed penalty notices were only applied to Group 04 (Dangerous and negligent acts) and Group 13 (Public order and other social code offences) offences, and to around 8% and 12% respectively of suspected offenders for those incident types. See Table 6.1 and Figure 6.1.