Context: Process Mining (PM) aims to discover processes and their characteristics from event logs recorded by information systems. There are dozens of general-purpose tools. The Brazilian judiciary wants to make the technology available to magistrates with little or no knowledge of the field of PM. Problem: The usability and comprehensibility of the available tools prevent their adoption by laypeople. In fact, these are two of the eleven challenges proposed by the IEEE Task Force on PM that are still little explored in the context of non-specialists. Methodology: Applied qualitative research, using User Centered Design (UCD) principles to guide the construction of the JuMP tool, conceived considering anthropological and sociological aspects of the Brazilian judiciary. For a year and six months, a team of PM specialists worked with representatives of the judiciary sector to produce, evaluate and evolve the new product. An experiment was performed to evaluate the usability and understandability of JuMP. Results: The study demonstrated that the use of a PM tool oriented to the application domain is fundamental for domain experts with little or no knowledge in PM to be able to make good use of it. Contribution: Demonstration that, unlike the prevailing practice in the area of PM, which prioritizes the provision of general purpose tools, the design of tools oriented to the application domain are prerequisites to improve usability and comprehensibility attributes. Finally, the work proposes a generic and adaptable methodology for developing specific-purpose PM tools and the experience of its implications to the design of the JuMP tool.