Crime situations are race against time. An AI-assisted criminal investigation system, providing prompt but precise legal counsel is in need for police officers. We introduce LAPIS (Language Model Augmented Police Investigation System), an automated system that assists police officers to perform rational and legal investigative actions. We constructed a finetuning dataset and retrieval knowledgebase specialized in crime investigation legal reasoning task. We extended the dataset's quality by incorporating manual curation efforts done by a group of domain experts. We then finetuned the pretrained weights of a smaller Korean language model to the newly constructed dataset and integrated it with the crime investigation knowledgebase retrieval approach. Experimental results show LAPIS' potential in providing reliable legal guidance for police officers, even better than the proprietary GPT-4 model. Qualitative analysis on the rationales generated by LAPIS demonstrate the model's reasoning ability to leverage the premises and derive legally correct conclusions.

翻译：犯罪现场调查是与时间的赛跑。警务人员亟需一种能够提供及时而精准法律建议的AI辅助刑事调查系统。本文介绍LAPIS（语言模型增强型警务调查系统），这是一个协助警务人员执行合理合法调查行动的自动化系统。我们构建了专门针对犯罪调查法律推理任务的微调数据集与检索知识库，通过引入领域专家团队的人工审核机制提升了数据集质量。随后，我们将预训练的韩语小规模语言模型权重在新构建的数据集上进行微调，并与犯罪调查知识库检索方法相结合。实验结果表明，LAPIS在为警务人员提供可靠法律指导方面展现出巨大潜力，其表现甚至优于专有的GPT-4模型。对LAPIS生成推理过程的定性分析表明，该模型具备运用前提条件推导出合法结论的推理能力。