1
a tracer for [something]
tracer 后接 for 表示追踪的目标。
The police hired a tracer for missing persons.
警方雇用了一名寻找失踪人口的追踪者。
追踪者
先理解核心含义，再看它在真实句子里的用法。
追踪者
an investigator who finds missing people or lost goods
The police hired a tracer for missing persons.
警方雇用了一名寻找失踪人口的追踪者。
A compound, element, or isotope used to track the progress or history of a natural process.
寻人寻物调查员
an investigator who is employed to find missing persons or missing goods
A round of ammunition for a firearm that contains magnesium or another flammable substance arranged such that it will burn and produce a visible trail when fired in the dark.
描图仪
an instrument used to make tracings
She works as a tracer, helping families find relatives who have gone missing.
她是一名寻人调查员，帮助家庭寻找失踪的亲人。
The museum hired a tracer to recover the stolen paintings.
博物馆聘请了一名追踪员来追回被盗的画作。
A tracer was called in to search for the lost documents.
一名寻物调查员被请来搜寻丢失的文件。
tracer 后接 for 表示追踪的目标。
The police hired a tracer for missing persons.
警方雇用了一名寻找失踪人口的追踪者。
of 也表示追踪对象，与 for 常可互换。
She is a tracer of missing goods.
她是一名寻找丢失货物的追踪者。
who 引导定语从句，说明追踪者的职责。
A tracer who finds missing persons must be patient.
能找到失踪人口的追踪者必须有耐心。
Not this
She tracers missing luggage for an airline.
Use this
She traces missing luggage for an airline.
tracer 是名词，意为“追踪者/调查员”，不能当动词用。表示“追踪、查找”的动作要用动词 trace；主语是第三人称单数时，动词用 traces。
Not this
He works as tracer for a detective agency.
Use this
He works as a tracer for a detective agency.
tracer 是可数名词，表示职业或身份时前面需要不定冠词 a/an。中文没有冠词，学习者容易漏掉 a，导致句子不符合英语语法。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
邮政失物调查员
The postal tracer was able to track the misdirected letter.
邮政失物调查员成功追踪到了那封投错的信。
失踪人员调查员
She works as a missing-persons tracer for the city police.
她为市警察局担任失踪人员调查员。
失物追踪员
A tracer of lost goods is often needed in large shipping companies.
大型运输公司通常需要失物追踪员。
熟练的追踪者
Only a skilled tracer could have followed those faint clues.
只有熟练的追踪者才能循着那些微弱的线索追查。
私人调查员
The family hired a private tracer to locate the missing cargo.
这家人雇了一名私人调查员来定位失踪的货物。
Use tracer naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
想象侦探沿线索(trace)追踪失踪者，加上 -er 表示“人”，就是 tracer：追踪者。
语域：formal 常见场景：警方寻人调查、保险理赔调查、失物追查 该义项指受雇查找失踪人员或失物的调查人员，多用于正式、职业化场合，如警务、保险或商业调查；日常口语中较少见。
与 tracer /ˈtreɪsɚ/ 押韵的词：racer、chaser、pacer、spacer（都读 /eɪsɚ/）。注意拼写相似的 tracker /ˈtrækɚ/、tractor /ˈtræktɚ/ 读音不同；laser /ˈleɪzɚ/ 中的 s 读 /z/，也容易混淆。
Dictionary facts from ECDICT, WIKTIONARY.