Plagiarism is a growing issue in science today. Sometimes plagiarism is simply the mistake of not properly citing a source even though the intention was there. Sometimes we make mistakes. There are many tools out there today that you can use to check your work, and your colleagues work. Some of these services are even free, and will give you information on your papers after scanning them.
Plagiarism can be difficult in science because some of the research scientist do is not entirely original. It is okay to use the work of other scientists of the past. Maybe they hit a stopping point in their research that you are trying to break through, and you need to follow the steps they took to get there. Regardless of intentions or motives, recognition needs to be given to the professionals first performing the work.
This above article written in 2012 evaluates two computer scientists from the University of Kansas who published three articles that earned them an invitation to present “their” work in Sweden. Portions of all three published work were confirmed to have been lifted from other professionals works. The article references a number of cases indicating increasing frequency of plagiarism.
Stop the plagiarism. The tools out there to catch it are too successful today and aside from the ethical dilemma brought foreword in plagiarism, being caught can severely damage your professional image.