The MP-Tracker™ method
MP-Tracker™ is a method developed by IDEF to classify missing-person reports by manner of disappearance and to guide the investigation before and during the field search.
It is a method of intelligence before the search: it organizes the information available, sets the primary hypothesis and the order in which the others must be checked, and records in writing the basis of each decision. It complements police, judicial and rescue protocols; it does not replace them.
- Developed by
- IDEFAuthor: Cristián Araos Díaz, forensic psychologist
- Core
- NASH-E/S classificationFive manners of disappearance
- Applies to
- Recent and archived casesReal time or retrospective
- Cited by
- Public Prosecutor's Office of ChileProtocol on presumed misfortune
The NASH-E/S classification
NASH-E/S establishes the manner of disappearance from explicit, reviewable criteria. It extends the classic manners of death (N.A.S.H.) to disappearances, where a person may also have left on their own or staged their own disappearance. The method weighs which manner the case evidence supports; it does not assign probabilities to the manners.
- NNatural
- A natural or medical cause.
- AAccident
- An accidental event.
- SSuicide
- Suicidal behavior. The presence or absence of a pre-suicidal state is assessed.
- HThird-party involvement
- Abduction, kidnapping, homicide or enforced disappearance.
- E/SEvasion or simulation
- A voluntary absence, or a disappearance staged by the person.
Methodological note. The classification is a working hypothesis subject to review by a competent professional. It is not an accusation or a proven fact, it does not replace or delay the report to the authorities, and its legal effects depend on the law of each jurisdiction.
What MP-Tracker™ adds to a search protocol
MP-Tracker™ is applied before and during the search, to organize the information available and to record in writing the basis of each decision. These are its operations:
- Establish the manner of disappearance with the NASH-E/S classification, using explicit and reviewable criteria.
- Set the primary investigative hypothesis and the order in which the others must be checked.
- Tell when a case calls for conventional investigation and when for non-conventional investigation.
- Place the case according to the time elapsed since the person was last seen.
- Build the missing person's mental map: point of departure, destination motivation, last known place, traceable routine and points of interest.
- Organize the analysis of persons of interest without suspending the area search.
- Apply the method retrospectively to archived or unsolved cases.
- Write the report so that every step is traceable and can be reviewed by a court.
Time changes the method, not the priority
The search for a missing person remains a priority at every stage. What changes as time passes is the method: the investigation moves from places to people, from the conventional search of areas to the analysis of persons of interest, without suspending the area search.
The missing person's mental map anchors that work. It starts from the point of departure, the motivation behind a possible destination, the last place the person was seen and their traceable routine, and adds the points of interest in their life: home, work or school, partner and former partners, friends, regular places and high-crime areas.
The Repetition (Epanalepsis) Model
The second pillar of the method looks for repetition: earlier absences, what the person usually did at that time of day, the places they would return to and what did not fit on the day they went missing.
It reduces uncertainty and turns data into decisions: likely scenarios, priority areas, team assignment and a written basis for each step, so that the report can withstand review in court.
Where the method applies
The method covers the whole life of a case: recent or active disappearances, ongoing investigations, retrospective (ex post facto) analysis, and archived or unsolved cases. It does not depend on a particular legal system: the NASH-E/S classification and intelligence before the search apply in any jurisdiction.
Among the professionals IDEF has trained are police officers from Spain, for whom the course is especially useful as a complement to the framework of Spain's National Missing Persons Center (CNDES) and its search protocols. The legal and procedural examples in the course come mainly from Chile and other Latin American countries; the method itself does not depend on them.
Origins and recognition
MP-Tracker™ was developed by IDEF under the direction of forensic psychologist Cristián Araos Díaz. Its link with official frameworks is documented:
“Adaptado de MP – Tracker (Rastreador de personas desaparecidas). IDEF. Instituto Delitológico de Ciencias Forenses y Periciales”
“Adapted from MP-Tracker (Missing Persons Tracker). IDEF. Instituto Delitológico de Ciencias Forenses y Periciales.” (Our translation.)
- 2015Presented at the First International Meeting on Criminal Profiling in Bogotá, Colombia, before the Colombian National Police and the United Nations Office on Drugs and Crime (UNODC). The author received a Medal of Honor from DIJIN, the Directorate of Criminal Investigation and INTERPOL of the Colombian National Police.
- 2017Presented at the University of Guadalajara, Mexico. Press coverage by Milenio (in Spanish)
- 2020Chile's Chamber of Deputies, Citizen Security Committee: Official Letter No. 271 invited the author, as “creator of the MP-Tracker Search Protocol and of the software of the same name” (our translation), to give his opinion during the passage of the bill on missing persons (Bulletin No. 12,392-25) that became Law 21,500 of 2022. Committee document (in Spanish)
Learn to apply MP-Tracker™
The Professional Certificate in Missing Persons Investigation and Search is the training program of the method: 150 hours, online, with mentoring in English.