Further to Jomot's posting, I was a bit puzzled when I found an article about the death of Lucy Fritze Darby in 1872.
Given her middle name, I thought she might be the mother of Tom Darby, the policeman, who gave the same middle name to one of his daughters.
Looking at the censuses in 1871 and 1881, Tom the policeman seemed to be born c1854, and had a daughter, Elizabeth Ann, born c1879. He was born in Barsby and his wife in Houghton. Looking at the marriage index, there is a matching record in 1877 in Billesdon District - Tom Darby to Sarah Ann Adams, as listed by Jomot.
In 1891, the family was in Hugglescote. Tom born in Rearsby c1854, rather than Barsby and Sarah in Houghton.
Also there in 1901 - Tom born c1854 in Barsby.
In 1861, Sarah was in Houghton with her widowed mother, Ann, b 1827 in Burton Overy
In 1851 Ann was in Houghton with husband, John, b Barkby c1823.
In 1871, Ann had married again to Joseph Rowley, and the family was in Evington.
John Adams married Ann Thrift in Billesdon District in 1848.
1841 Census in Burton Overy:-
John Thrift 40 b 1801
Alice Thrift 40 b 1801
Ann Thrift 15 b 1826 (bapt 5th March)
Jane Thrift 11 b 1830
In 1861, Tom was in Rearsby with his parents Thomas and Lucy Fritze. Unfortunately, because of the bad handwriting, it is transcribed as:-
Thomas Darby Head 31 b 1830 Rearsby
Lucy Roaster Darby Wife 28 b 1833 Rearsby,
John Darby Son 7 b 1854 Rearsby
Thomas Darby married Lucy Fritze Kirk in Barrow on Soar District in 1851.
In 1851, Lucy was in Rearsby with her father, Edward, b 1789 in Thrussington.
Also in 1841 - two sisters but no mother.
Edward Kirk, bapt in Thrussington on 15th November 1789, son of Edward and Ann.
On the baptisms, his wife was Anne - Lucy transcibed as Foitze - 2nd Jan 1833.
Probable marriage on 20th July 1814 in Rearsby to Anne Dalby.
There is a baptism of a John Fretts in Burton Overy in 1778, which may have been the origin of the Fritz(e) middle names. Might also be a corruption of Thrift.
John Thrift married Alice Sturges in Marston Trussell - 3rd July 1818.
This link has details of Thrift graves in Burton Overy:-
http://www.lrfhs.org.uk/Burton%20Overy%20Book.pdfDavid